IN THIS ISSUE - americanradiohistory.com in this issue. This second scoop is ... will not be doomed...

IN THIS ISSUE:

Legality of -V "Policies" Clarified

A Klistron TV Sweep Generator

High Qualit/ Analysis Series

"Aspen"-Philco's Built -In -V Antenn

ESFETA TV Training Program

fro essiona Radi

SEPTEMBER, 1)49

P.R MALLORY/1C° Inc

High rfemperature is Tough LOn Long Life ...

4fvortws4

Mallory Capacitors Can Take It !41111111b.

it's one thing for a capacitor to have long life.But it takes a MALLORY CAPACITOR to sustainits long life at high temperatures. Tests prove thatthe characteristics of Mallory FP Capacitors arepractically unchanged after 2000 hours at a

temperature of 185° F.

Rigid manufacturing controls guard MALLORYCAPACITORS against contamination-the enemyof long life. Mallory Capacitors are untouched byhuman hands; production workers vyear rubbergloves. And Mallory specifications on chloridecontent of the gauze are even more rigid than onhospital gauze, for gauze is the base on whichaluminum is sprayed to create the anode plate.

You can depend on Mallory Capacitors for longershelf life-longer life in an inactive set-lower

Don't Miss the Mallory Television .Service Encyclopedia.Get Your Copy From Your Mallory Distributor . .. Only 35e.'

RF impedance-ability to withstand higherripple current.

Mallory Capacitors cost no more than ordinarycapacitors. They're easy to install, and N% hen they'reinstalled they're de/tent/a/de ... and that meansthe kind of service that satisfies customers. Orderfrom your Mallory distributor.

NEW IMPROVEMENTS IN MALL( IRVFP CAPACITORS ... Feature strongeranode tabs-withstand higher dis-charge currents-improved high surgeseparators-still greater heat resistance-extra heavy rubber seal-heavycathode tab-special etched cathode.

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EDITORIALby S. 11. COWAN

More On TV "Policies"Our scoop "Legal Bombshell Hits TV

Service Policies" last issue caused thegreatest furore since TV's inception. Now,as a result and sequel, we proudly call,your attention to the article "Legality of -

TV `Policies' Clarified," appearing on page12 in this issue. This second scoop is the'official opinion handed down by the NewYork State Insurance Department, the bodyresponsible for supervising insurance poli-cies and contracts.

Our "Bombshell" article pointed out thatindependent radio service organizationswill not be doomed to oblivion by manu-facturer controlled TV service subsidiaries.Independents will only fail if they neglectto conduct their businesses in businesslikemanner, and if they prove themselves tech-nically incompetent. Incidentally, in Augustwe typographically erred in stating the"Bombshell" article continued on page 31,whereas it carried over to page 36. Thanksto the hundreds of you who called this toour attention.Hurrah For October

As reported here in July, Pennsylvaniaand New York State radio service dealers,service organizations and independents, co-operating with broadcasters, manufacturersand jobbers, will hold a two -state cam-paign making October 1949 "PreventiveRadio Maintenance Month".

This is a grand venture. Let's hope thatin 1950 it will be a nation-wide campaignrather than a mere two -state project. Inconjunction with the October campaign,which will result in many thousandsof extra service jobs which would nototherwise have been obtainable, the Phila-delphia Radio Servicemen's Assn. will holda 3 -day convention, (Sept. 18-19-20), whichreally will be a series of technical clinicsto which all technicians are invited. Inlike manner, technical assistance will begiven all New York State servicemen bymeans of the Empire State Federation ofElectronic Technicians' series of clinicswhich begin the first week in September.A series of 60 lectures is being given inkey cities. The complete schedule appearson page 24, this issue.

Radio technicians everywhere would bewise in following the lead of Pa. and N.Y.First, organize local associations, then col-laborate with like groups in your state soeventually a state federation having unityand strength can be formed.Color TV

The announcement that full color TVtransmission and reception is now possiblewill undoubtedly make many potential TVset buyers hold off making purchases now.Actually there is no telling when orwhether such color TV sets will ever besold commercially. Our advice to TV deal-ers is to candidly tell the potential TV setbuyer that present-day TV sets are worth-while investments . . . and that if theywant to wait for color TV, they may sacri-fice much more enjoyment than the longwait justifies.

Sanford R. CowanEDITOR & PUBLISHER

Samuel L. MarshallMANAGING EDITOR

COWAN PUBLISIIING Corp.342 MADISON AVENUE

NEW YORK 17, N. Y.

Vol. 10, No. 9

SEPTEMBER, 1949

Trade Flashes 4

Legality of TV "Policies" Clarified 12

New developments on this all important subject

A Klystron TV Sweep Generator, by Allan Lytel 15

Theory and operation of this unique test equipment

High Quality Analysis Series, Part I, by C. A. Tuthill 17

Another in this popular series

"Aspen", Philco's Built In TV Antenna, by John Pell 20

Theory, operation and adjustment of this new and interesting

development in TV reception

Circuit Court 23

General Electric 376, Temple Model G-1430

Association News 24

ESFETA TV Course, PRSMA Convention

New Products 25

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: 22 per year in the United States, U.S. Possessions & Canada:elsewhere $3. Single copiei: 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.

RADIO SERVICE DEALER SEPTEMBER, 1949

if you knowwhat's in this book

Liand pass the informationon to your customers...

we'll all benefit!* YOU... Customer Satisfaction

More Sales* YOUR CUSTOMERS

Better TV Pictures* WE...Your Good Will-

More Sales

The prospective TV -set owner is interestedprimarily in the PICTURE HE WILL SEE. And youare interested primarily in being sure he gets themaximum enjoyment out of his set.

But to sell effectively, you must know theright answer to every question about TV sets ANDMORE BESIDES. The Sales Manual, "Sell a TVPICTURE", is one of the most important guides avail-able for selling TV. YOU CAN'T AFFORD NOTTO READ AND STUDY IT. Do you know, for ex-ample, that it has been proved time after time that"an inferior set with a good antenna will out-perform a better set with a poor antenna"?

This 16 -page book was especially plannedfor those TV dealers who want to become morefamiliar with the factors of importance in producingthe best picture.

"Sell a TV PICTURE" gives power -packedselling information ... exact, scientific data in easilyunderstood terms . . . that will help you helpyour customers.

Written and prepared by radio -electronicexperts, the manual is a new approach to TV pic-ture selling and all information contained thereinis backed by results from laboratory and field tests.

Write for your free copy.

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FACTORS OF INTERESTFOR -SALESMEN OF

* SELL A TV PICTURE FOR CUSTOMER SATISFACTION

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-11411NF ANTENNASAMERICAN PHENOLIC CORPORATION1830 SO. 54TH AVENUE CHICAGO 50, ILLINOIS

2 RADIO SERVICE DEALER SEPTEMBER, 1949

HERE'S HOW IT WORKS ...

A.B.

C.

Electrostatic fieldIons are bent away from normal axis oftube by electrostatic fieldExternal magnet neutralizes the effect ofthe electrostatic field on the electrons

D. Electrons follow a straight lineHeavy ions are thus trapped in the electrongun while the electrons pass through tostrike the fluorescent screen.

ION TRAP IN SYLVANIATELEVISION TUBESASSURES HUNDREDSOF HOURS FREE FROMSCREEN BURNS

Owners of television sets equipped with Sylvania Televi-sion Picture Tubes report their screens still bright andunblemished after more than 1000 hours' use. Much creditfor this top quality performance belongs to Sylvania scien-tists who hold the basic patents on the magic "ion trap."With this device these scientists prevented destruction ofthe fluorescent screen by heavy ion bombardment. So suc-cessful is this ion trap that now many other major TV tubemakers are using it under agreements with Sylvania.

These same Sylvania Television Tube scientists are nowdeveloping shorter large -screen picture tubes and specialtubes for uhf television. Their continued research makesthe Sylvania label your guarantee of the newest and finestin television picture tubes. Sylvania has a complete line ofall -glass and glass -metal types for television and generalpurpose cathode ray applications. They are available nowfrom your Sylvania Distributor.

Write for free characteristics and TV set complementchart. Advertising Department, Bol R-1809, Emporium, Pa.

SYLVANIAELE RICRADIO TUBES; CATHODE RAY TUBES; ELECTRONIC DEVICES; FLUORESCENT LAMPS,FIXTURES, WIRING DEVICES, SIGN TUBING; LIGHT BULBS; PHOTOLAMPS

RADIO SERVICE DEALER SEPTEMBER, 1949 3

titiaABOUT

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SPRAGUEDISC

CERAMIC BYPASS AND

COUPLING CAPACITORS

These new ceramic units-no big-ger than a dime-find dozens of by-pass and coupling uses in both stand-ard and FM as well as televisionequipment. They have higher self -resonant frequencies than convention-al capacitors and fit neatly acrossminiature tube sockets. They're cov-ered with a tough, protective coatingwhich guards against moisture andheat. Sprague Disc ceramics are avail-able in both single and money -savingdual capacitors.

Use Sprague Disc ceramics when-ever circuits call for ultra -compact,bypass or coupling capacitors. Eachunit is clearly stamped with capaci-tance. All capacitors are rated at 1000v. test, 500 w.v.d.c.

See these remarkable new capaci-tors at your Sprague distributor to-day! Write for bulletin M 431.

SPRAGUE

PRODUCTS commit/Distributors' Division

of the Sprague Electric ContpanyNORTH ADAMS, MASS.

TRADEFLASHES

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

PRSMA Convention & ExhibitPhiladelphia Radio Service Men's

Association announces a 3 -day con-vention and exhibit to be held inPhiladelphia on Sept. 18, 19, and 20.This exhibit is part of the Oct. 1949Preventive Radio Maintenance Monthprogram. Representatives of variousmanufacturers, and others are scheduled to deliver technical talks in anelaborate program which has been ar-ranged. See page 29 for further de-tails.

RMA-IRE Fail MeetingThe program of the Radio Fall

Meeting of members of the RMAEngineering Department and the In-stitute of Radio Engineers, scheduledfor Oct. 31 and Nov. 1 and 2, at theHotel Syracuse in Syracuse, N. Y.,is substantially complete, according toVirgil M. Graham, associate directorof the RMA Engineering Departmentand chairman of the committee ar-ranging the meeting.

ESFETA Launches State -WideTraining Program in TV

Empire State Federation of Elec-tronic Technicians Associations (NewYork) announces a state-wide TVtraining program in which Industryparticipates to the extent of providinglecturers for a planned TV course.This project represents the most am-bitious program ever undertaken byany organization for this purpose, en-tailing 64 lecture units given by rep-resentatives of 17 firms. See page 24for further details.

Philco Service Managers MeetA TV service managers' convention

was held in Philadelphia, on July 27,28, and 29, at which the Philco Cor-poration was host. Shown at the vari-ous panels held during this meetingwas the complete new line of PhilcoTV receivers. The feature of this con-vention was the revelation of Philco'snew self contained TV antenna, calledASPEN. Speakers included, J. M.Skinner, Jr., Vice President, Serviceand Parts Division; Ken Kenyon,General Manager, Service Division;H. T. Paiste, Jr., Manager, Field

Engineering; Caywood Cooley, Super-visor, TV Training; John Pell, Man-ager, TV Service; B. P. Haines, ChiefMechanical Engineer, Electronics Di-vision; H. H. Harris, Chief FactoryEngineer, Factory Engineering De-partment; Ray Robinson, Supervisor,TV Field Service; Win. E. Bradley,Director of Research, Research Divi-sion, Jack Cherry, Manager, Acces-sory Sales; Wilson Miller, Field Ser-vice Engineer; Joe Fisher, ProjectEngineer, Research Division; and BillNagy, Promotion Manager, ServiceDivision, who did an excellent job ofMCing. Ted Lucas, Jr., Director ofPublic Relations, and his charmingwife were tops as hosts.

GE Pocket AidA convenient carrying case known

as the Pocket Office, now availableto radio and television servicemenand dealers through General Electricand Ken Rad Tube Distributors, isbeing examined by Mauro Schifino,(second from left), Sales Manager

for Rochester Radio Supply. Lookingon, from left to right are CharlesRichardson, District Representativefor G -E Electronic Tubes and Partsin Upstate New York; A. D. Lam-phier, purchasing agent for RochesterRadio Supply; and Art Piccarreto, aRochester service technician.

DuMont Proffers New TV PlanThe Allen B. Du Mont Laborator-

ies, Inc., will present to the FederalCommunications Commission, at hear-ings to commence in WashingtonSeptember 26, a program to utilizethe Very High Frequencies and the

[Continued on page 6]


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Kit! MAST( Ito VOLTOMMYST ''''cl.°4

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/VOLT° HMYST* has no equal forfast, accurate servicing

MEASURES ... si DC VoltageCapacitance if AC Voltage

if DC Current if Resistance

Truly the "master" electronic multi -meter, the RCA WV -95A combines inone instrument virtually every measuringfacility required in the service shop. Itmeasures ac and dc voltages to 1000 volts,dc current from I microampere to 10amperes, resistance from 0.1 ohm to1000 megohms, and capacitance from 4mmf to 1000 mf. A polarizing voltage isincluded for the measurement of elec-trolytics. The carefully balanced meter isvirtually burnout -proof; and has a full scaleaccuracy of +2 %. Zero -center indicationis provided for discriminator alignment.

The entire electrical system of theWV -95A is insulated from the metal casewhich may be grounded separately.

When used with the RCA WG-275accessory diode probe, the WV -95A willmeasure rf voltages in communicationequipment and coaxial lines, and peak -to -peak voltages of recurrent pulses in syncsignal generators, television receivers,*Trade Mark. Reg, U. S. Pat. Off.

etc. The WV -95A can also be used withthe RCA WG-284 accessory high -voltageprobe to measure up to 30,000 dc volts.

For full details, ask your RCA TestEquipment Distributor for Bulletin 2F721-or write RCA, Commercial Engineer-ng, Section 55IX, Harrison, N. J.

SPECIFICATIONSDC VOLTMETERSix Ranges 0 to 5, 10, 100, 500, 1000 do voltsInput Resistance, all ranges 11 megohmsDC AMMETERSeven Ranges:

Through DC Amplifier0 to 10, 100 microamps; 0 to 1, 10, 100 ma.

Direct to Meter Movement 0 to 1, 10 amperesOHMMETER

Six Ranges 0 1 ohm to 1000 megohmsC -scale Indications

10, 100, 1000, 10000 ohms; 0.1, 10 megohmsAC VOLTMETER

Seven Ranges0 to 1, 5, 10, 50, 100, 500, 1000 RMS Volts

Input Resistance and Capon0.5 megohm shunted by 125 mmf.

Frequency Response 30 to 20,000 cpsCAPACITANCE METER

Six Ranges 4 mmf. to 1000 mf.Center -scale Indications

100, 1000 mmf.; 0.01, 0.1, 1, 10 mf.RF VOLTMETERRanges: (Requires WG-275 accessory probe)

From 30 cps to 17.5 Mt.0 to 5, 10, SO, 100 RMS Volts

To 75 Mc 0 to 5, 10, 30 RMS VoltsTo 250 Mc 0 to 5, 10 RMS Volts

Dimensions 10" high, 131/2" wide, 71/2" deep

For Test Equipment you can trust ... see your RCA Distributor

RAD/0 CORPORATION of AMERICATEST AND MEASURING EQUIPMENT HARRISON.

TIUDE !FLASHESI pa!ie

Ultra High Frequencies as carefullyintegrated vomponents of a nationaltelevishon system that will benefitviewers in ]host of the country's 1411

Illetrttpolitall dist ricts.

Capacitor Color ChartSimply match colors and read ex-

act values. That's the idea of theDuranite Deeooler ('hart issued byAerovox Uorlyoration c.f New Rol -ford, Mass. Printed in colors, thischart shows the UM_ color band

MOLDED TUBULAR PAPER CAPACITORS

It +11

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coding fort wrrlrled tubular paper ca-pacitors, with corresponding numer-ical values et capacitance, toleranceand voltage. All the user oboes is com-pare the (.01.w -coded tubular withthe units on the chart until the colorbands match, whereupon values oreread at a glance.

Engineering IndexAnnouncement has been received

from John F. Rider, president of theElectronics Research Publishing. ('oo.,Inc., that the Electronics EngineeringMaster Index for 1947 and 19-1,,, andthe index for January -June 1949 willhe published during November 1919.

Sylvania Promotional CampaignThe Radio Division of Sylvania

Electric Products Inc. has announceolthat it will continue its program ofradio serViCelllan prompt if In frontSeptember through 1)ecemher thisyear. The program will include a

series of national advertisements inthe Saturday Evening Post, Collier's,Life and Radio 6; Television Best,

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A SMALL SIZEVOLUME CONTROL

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KNOB MASTER FIXED SHAFT

fits 90% of AM, FM andTV shaft knobs. No alterationexcept cutting to length. Knurled,flatted and slotted to accommodateknurled push -on knobs, spring -typepush -on knobs or set screw knobs.Ends spread for fitting oversize orworn knobs. 3" length meets televisionrequirements. No shaft inserts needed.

CUSHIONED TURN.

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O RESILIENT

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COMPACT 15A6" DESIGN and 1/4" longbushing permit easy installation in the most

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permits removal ofKnob Master Shaft and re-placement with any of 11special fixed shafts, in lessthan a minute, using only apocket knife or screwdriver.

NEW TYPE

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INTERCHANGEABLE

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/1 \/

STURDIER AND MORE BEAUTIFUL.

Rugged, molded control base andswitch enclosure are colored dis-tinctive IRC blue. All metalparts are non-ferrous materialnickel -plated for lustrous finishand resistance to corrosion. Cus-tomers will like the Type Q'srich precision appearance.

SEEING IS BELIEVINGIn an actual field test, IRC Q Controls and Interchange-able Shafts were demonstrated to a large cross-sectionof radio and television technicians. All were enthusiasticover the unique features of these revolutionary newcontrols. Because of their versatility, ease of use, anddependability, we believe they will become the mostwidely used controls in the industry.

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Now, with IRC's versatile 0 Control Line and SpecialFixed Shafts, you can service virtually every type ofsmall control requirement-in a minimum of time.Ease of installation-even in crowded chassis; one -minute replacement of shafts for specials; shaft andbushing lengths to meet current radio and TV

PLUS THESE EXTRA CONSTRUCTION ADVANTAGES

very ontro , no ' as er a n erc angeable Fixed Shaft or Switch is simply designed,ruggedly constructed, safeguarded by complete pro-duction testing. Control base is precision molded ofhigh strength, low moisture absorption bakelite.Contractor is IRC patented one-piece dual unit ofthin high -stress alloy. One-piece collector ring andcenter terminal are silver-plated brass. And theresistance element is the best IRC ever manufactured!

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For complete details of IRC's revolutionary new Type QControls and Interchangeable Fixed Shafts, write us today.IRC Q Controls mean easier AM, FM and TV servicing for you-more convenience for you. Get the full story. Mail couponfor our new Catalog DC -1.

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Big things often come in little packages . . . So it is with thesuperlative new Shure "Vertical Drive" Crystal Cartridges.They reproduce all the recorded music on the new fine -groove recordings-a reproduction that meets the strictrequirements of high compliance and full fidelity. The "Ver-tical Drive" cartridges are requisite for the critical listener-the lover of fine music. They are especially recommendedfor those applications where true fidelity is essential.

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TIRADE FEtsims

which 'will ht -tipplemented by newpoint of sale merchandising, materialsupplied to ,:erviee-dealers in kit form.RCA 16" TVs Shipped

Initial shipments of three new RCAV iotor television receiver models fea-turing tiiii pditich metal -coned pic-tore tulle Het 1 ti scut to diStribU'"t,r,, Allan B. Mills, General SalesNlanager of the IZ( 'A Victor HomeInstrument Department, announcedrecently.

IRE West Coast ConventionProof of t he Far West's rowing

importance in el, ,etrorii - up-ied 1111- month by the dis!'. H -teed

list of technical papers -ci:ipresentai ion at the 1949 IIfl \VestCoast Convention in San Francisco,Aug. 30, 31 and Sept. 1, at San Fran -

lc And i toriuna.

National Electronics ConferenceTH 1919 National Fleas

lereticii, an annual nationalresearch, develni,I,.. and.

,;1,1,11 ea t ion, the conference .. beheld _Monday, Tee,day, and 1V..i!

:(.1,aaniter 211, 27. and 2' 'I: the

Ward Appoints So. Cal. Rep

l'1,1Lt(-\\;Itt,i 11e:H.11 -ago.

The \Vard ind,a Division or the Galiriel t'or, .. hasappointed the .J. T. 11 ill Sali -Los Angeles, as it- Si itithern I Hli-fornin representative-, according to,Terry Hill, executive head of the fac-ti,ry rep firm that has specialized in

fiir more than a score ofctur

RMA Production FiguresOne million or more teh-vision re-

ceivers were produced during the firsthalf of 1949, the Radio Manufactur-ers Association estimated today onthe basis of reports received frommember -companies. This slightly ex-ceeded total TV set production duringthe whole of MIA set manufac-turers' output ti,talled 913,071 TVsets.

Following is the lireakdo \VII in radin and television set production by

A incuiliiiN for the first half of1949 :

JanuaryFehrunryMarch (five weeks)AprilMayJune (five weeks)

TOTAL

I0 RADIO SERVICE DEALER SEPTEMBER, 1949

VY

fa -/A t

ROTOR

At last ...the ultimate in rotators...a triumph in engi-neering skill. Months and months of patient research anddevelopment ... now ... we are proud to announce ourlatest triumph ...the Radiart "Little Giant" TELE-ROTOR!Not a single factor has been overlooked to bring you thebest ... true to Radiart tradition that makes Radiartproducts ... THE STANDARD OF COMPARISON! To youwho have wanted a superior rotator that out -performs allothers ... THIS IS IT!

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Check These Features:

Heavily Reinforced Die-castHousing

Two (51/2" Ball -Bearing Races

Heavy-duty Precision Gears Positive Stop at End of Rotation

Takes 70" to 2" Upper and LowerMasts

Motor Instantly Reversible

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THE RADIART CORPORATIONCLEVELAND 2, OHIO

Manufacturers of the Famous Red Seal Vibrators

RADIO SERVICE DEALER SEPTEMBER, 1949

zkciatitikTV "POLICIES" CLARIFIED

The New York Insurance Department, through Deputy SuperintendentAlfred J. Bohlinger, on August 25, 1949, released the followingstatement with reference to the opinion rendered recently by Att. Gen.Nathaniel L. Goldstein, in connection with television service contracts.

SOME TIME AGO, several of the lead-ing manufacturers of television

sets inquired of this Department asto whether or not television servicecontracts proposed to be used by themviolated the provisions of the NewYork Insurance Law. Dealers, as wellas service men, made similar requestsof this Department relative to theircontracts. Examination of the con-tracts, as well as the practices fol-lowed in the television business, in-dicated a general pattern. A majorityof the contracts submitted by manu-facturers indicated that the companieseither directly or through subsidiarycorporations, or dealers, proposed uponthe sale of a television receiver to in-stall and keep it in repair for a speci-fied period of time. A charge, in ad-dition to the sale price of the set, wasproposed to be made for such installa-tion and service. The contracts alsoprovided for renewals thereof to keepthe sets in repair. Under the originalcontract, as well as renewal agree-ments, replacement of parts wasincluded in the so-called "servicecharge". In all instances, the contractswere limited to keeping the receiverin proper operating condition in theevent of failure solely from normalu s e without intervening externalcause, such as fire.

There also came to the attention ofthe Department the fact that servicemen who were neither manufacturersnor dealers were making similaragreements with the owners of tele-vision sets.

The Insurance Department soughtand has received the opinion of theAttorney General relative to the valid-ity of the various proposed plans ofoperation. From numerous inquiries

made to this Department since thepublication of the Attorney General'sopinion, it appears that persons andfirms engaged in servicing televisionsets are of the belief that all formsof service contracts are now in viola-tion of the Insurance Law and henceillegal. In order to correct this im-pression, the Department desires tobring to the attention of the publicand those engaged in the televisionbusiness the Department's interpreta-tion of the opinion as follows:1. Upon the sale of a television re-

ceiver, the manufacturer, includ-ing a wholly owned subsidiary cor-poration, may for a separate con-sideration enter into a contractwith the public whereby it agrees,for a stiuplated time, to maintainthe receiver in workable order andto replace parts.

.2 A dealer who sells a television re-ceiver may do likewise.

3. Service contracts connected withthe sale of a receiver must belimited to keeping it in properoperating condition (including re-placement parts) because of fail-ure arising from normal use with-out intervening external cause, asfor example, fire.

4. Neither a manufacturer (includ-ing a wholly owned subsidiarycorporation) nor a dealer may re-new such a contract.

5. A service organization which isneither the manufacturer nor thedealer of a television set may notmake such a contract.

6. Under the opinion of the AttorneyGeneral, all service contracts orrenewals thereof made by serviceorganizations, and renewal service

contracts of manufacturer., anddealers, are not automatically vio-lative of the Insurance Law andillegal. The question thereforearises as to what forms of suchcontracts are valid. The InsuranceDepartment desires to inform thepublic that any service contractor renewal thereof made by a ser-vice organization, and a renewalservice contract made by a manu-facturer or dealer, pursuant towhich a service organization, man-ufacturer or dealer agrees for afixed fee or charge to make oneor more specified inspections andplace a television receiver in goodworking order, and to make suchfurther inspections or repairswhich may be required during theterm of the contract, will be eon-strued to be valid. Such s con-tract may not include replacementof parts, shall be limited to repairsnecessitated by normal use endmust exclude repairs necessitatedby external causes.

The Department further calls at-tention to the fact that the aforemen-tioned rules regarding the legality orillegality of television service con-tracts will be applied in passing uponthe service contracts affecting otherappliances, machines, equipment ordevices whether used in places of bus-iness or in residences.

It should be kept in mind that thisDepartment is concerned only withdetermining the question of whetheror not a given agreement is violativeof the insurance laws of the State ofNew York. The Department cannot,and does not, pass upon any otheraspects thereof.


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Ask ?our Gen:I-al Electric tube distributor to show youthe Pocket Office, and give you the details on how tosecure this up-to-date aid to efficiency. Then use it toconvert eve -y minute of yo ar working time into profits!Electronics Department, General Electric Cc mpany,

Schene7tady 5, vet", York.


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TV SWEEP GENERATORby Allan Lytel

Author of TV Picture Pro jecton & Enlargement

The klystron tube, which operates on a principle entirely different than conven-tional vacuum tubes, is primarily designed for UHF applications. In the productdescribed in this article its characteristics are made use of to result in aninstrument that is excellently suited for TV alignment. In view of the probab-ility of UHF TV in the future, in addition to its present usefulness, the rad-io service dealer should acquaint himself with the potentialities of this device.

THERE are many possible methodswhich are used to produce

Sweep Generators designed for visualalignment of tuned circuits. One ofthe most highly developed methodsis the beating together of two oscil-lators in order to produce the requiredfrequency modulated sweep. This in-strument, the Mega -Sweep, is uniquein that it uses two Klystron oscilla-tors of a design which is quite dif-ferent from the conventional typeof oscillator tube. In this test equip-ment the output covers the entirefrequency range from 50 kilocyclesto above 500 megacycles while pro-viding a frequency sweep up to 30megacycles. Because of the use ofKlystron oscillator tubes, which oper-ate at a frequency of approximately10,000 megacycles (type 723) andmixing crystals (Silicon type 1N21,1N23) there is inherently a tremen-dous range of operating frequencies.

This extremely wide frequencyspectrum requires the use of an un-usual type of wave meter. This wavemeter is a resonant cavity tuned bymeans of a plunger which is attachedto a micrometer head. It is not theactual frequency of either of the twoKlystrons which is important butrather the actual output frequencywhich is the difference between thesetwo signals. No conventional wavemeter could possibly cover this fre-quency spectrum. In addition to thewave meter there is an attenuatorwhich is used to obtain the proper bandwidth. Also incorporated in the cir-

The Kay Mega -Sweep

cuit are various switches as well asa meter to read crystal current. Thefunctions of these controls will beexplained under "Operation."

The Klystron OscillatorSince this special microwave tube

is very probably unfamiliar to a greatnumber of service technicians, a briefdiscussion of its characteristics anddesign must necessarily precede adiscussion of the operation. In gen-eral, the Klystron falls into a classof tubes which operate on an entirelydifferent principle from conventionalvacuum tube circuits. The theoryof operation may best be describedby noting that this is a velocity -

modulated type of tube designed topermit operations in frequencies farbeyond the capabilities of normal os-cillators. Figure 1A is a schematicof a Klystron tube which is not usedin the Mega -Sweep ; however, thistype is easiest to understand.

Electrons are emitted from thecathode just as with an ordinary tube;these electrons are attracted by apositive voltage on the acceleratorgrid. The electrons are then passedthrough a pair of grids known as"buncher" grids. Assume that thebuncher grids are attached to a tunedcircuit so that one grid is tied toeither end of the circuit. If an alter-nating potential is applied to these

RADIO 'SERVICE DEALER SEPTEMBER, 1949 15

buncher grids the electrons will begrouped or bunched because of thesignal upon the two grids. Since thesegrids are at either end of the tunedcircuit there will always be a differ-ence of potential between the twogrids. Some of the electrons will havetheir velocity increased because theywill be pulled by the positive gridand some electrons will have theirvelocity decreased since they will bepushed from the negative grid. Thegroup of electrons which is betweenthe buncher grids at any momentwill be bunched in the foregoingfashion. Very few of these electronshit these grids but they pass throughin groups.

As these electrons travel down thetube the bunching will become moreand more pronounced. In any givengroup of electrons the slow ones willfall back slightly and the fast oneswill move ahead slightly which in-creases the bunching action as theytravel down the tube. This actionmay be seen by referring to Fig. Iwhere the electrons traveling in thedrift space become more tightlybunched.

The group of electrons are thenintercepted by another set of gridsknown as the "catcher" grids. Thesegrids are also attached to anothertuned circuit. All that is necessary,in order that the buncher grids willbe able to give up energy to thecatcher grids, is to maintain the prop-er distance between these two groupsof grids. Electrons coming from thecathode are accelerated by the firstpositive grid, are then grouped by thebuncher grids, and finally give uptheir energy to the catcher grids.There is an increase in energy be-tween the first set of grids and thesecond set of grids because the elec-trons tend to group themselves moreclosely as they travel through thedrift space. In traveling through thecatcher grids the electrons give up agreat deal of their energy which theyattained in their travel. This releaseof energy causes oscillations in thetune circuit attached to the catchergrids.

The final element in the tube is acollector or plate. This gathers theelectrons and removes them from thetube since the electrons have no fur-ther useful purpose. Both the buncherand catcher grids have a positive d -cpotential applied which is used toaccelerate the electrons toward theplate. Since there is a greater outputfrom the catcher grids than is neededfor the buncher grids, this tube canact as an oscillator. Feedback is

ACCELERATORGRID+ D.C. BUNCHER

GRIDS

CATHODE

(A.c.)--

1-akost,+ D.C. -A-

CATCHERGRIDS PLATE

ACCELERATORGRID

+ D.C.CATHODE

GRIDS

it4---tsgoi

+ D.C.c

( Rancherand Catcher)

-B-

REPELLERPLATE

- D.C.

Fig. I. Two types of klystron operation.

necessary from the output to theinput, as with any oscillator, and thisis usually obtained by means of acoaxial cable which takes a portion ofthe larger signal and feeds it backin the proper phase to the bunchergrids in order to sustain oscillations.An output signal may be obtained byinductively coupling to the tune cir-cuit of the catcher grids. Amplifica-tion occurs in this velocity modulatedtube because, in actual operation,electrons pass through the bunchergrids in a steady stream and arriveat the catcher grids in bunches.

The resonant circuits associatedwith this oscillator are cavities whichrepresent tuned circuits having a veryhigh "Q." This represents the fun-damental operation of any oscillatorsof this general velocity modulatedclass. These can be operated as am-plifiers, oscillators, or mixers; we arehere concerned with their operationonly as an oscillator. The frequencyof operation of the oscillator may bedetermined by varying the geometryof the tuning cavities. This may bedone by metal plugs which may bescrewed in or out of the cavity there-by changing its resonant frequency.

The Reflex KlystronThe Klystron oscillator is used in

the Mega -Sweep. The design of thisreflex Klystron is somewhat moresimple than the ordinary velocitymodulated Klystron with two setsof grids. In Fig. 1B the reflex Kly-stron has only one set of grids whichfunction as both the buncher andcatcher grids. The plate in this os-cillator has a negative voltage henceit is known as the repeller. Electrons

travel from the cathode through thegrids, acting as buncher grids, andare repelled or reflected back by thenegative voltage on the plate. On thereturn trip of the electrons the gridsnow act as catcher grids. If theproper voltage is maintained on therepeller plate this tube will act asan oscillator since the bunched elec-trons will pass through the grids thesecond time in the proper phase togive up their energy. Feedback isobtained in this manner and the tubeappears much more simple in con-struction.

The frequency output may be variedby changing the potential upon therepeller plate; it is this voltage whichdetermines how long it takes for theelectrons to make a round trip journeyuntil they are removed from the tubeby the accelerating grid. This chang-ing repeller voltage also somewhataffects the operation and amount ofoutput for this tube. These 723 typetubes are known as Pierce -ShepardReflex Klystrons and have a cavitysealed in the tube which is tuned bymoving the tube envelope in order tovary grid spacing.

A saw tooth voltage is applied tothe repeller tube of the reflex Kly-stron in order to provide a variablefrequency output. Changes in theactual resonant frequency of this os-cillator may be obtained by changingthe spacing between the grids. TheCoarse Frequency Adjustment on thefront of this sweep oscillator changesthe grid spacing of the Klystron whichis the local oscillator.

The Mega -Sweep OscillatorBy means of the reflex Klystron


it is possible in this instrument toproduce a very wide range of fre-quency output with an exceedinglywide frequency deviation. The 723tube provides approximately 35 milli -watts output over a frequency bandfrom 8500 to 9100 megacycles. Takingany particular point in this band achange in repeller voltage will pro-duce a frequency modulation with atotal frequency excursion of 30 mega-cycles. By means of internal changesit is possible to extend the frequencysweep to as much as 80 megacycles.The output from the two reflex Kly-strons is mixed in a wave guide con-vertor which provides a constant loadover the entire frequency range. Theoutput voltage is supplied at an im-pedance of 50 ohms which resultsfrom the crystal impedance and re-sistors in parallel. The actual outputvoltage is approximately 0.1 volt overthe entire range. It is possible to in-crease this output to 0.4 volts by rais-ing the impedance to 300 ohms.

A thyratron (miniature type 2D21)provides the sweep voltage for therepeller of the first oscillator. Sweepvoltage is at a rate variable between50 and 100 times per second. SweepAmplitude varies the sweep voltagein order to provide a frequency sweepfrom 30 kilocycles to 30 megacycles.

Sweep voltage which is applied tothe repeller of the first oscillator isbrought out through jacks; this maybe applied to the sweep amplifier ofthe cathode ray oscilloscope and usedas the sweep voltage for this indicat-ing device. By this means there is nonecessity for synchronization or phasecontrols as is the case with othertypes of sweep oscillator outputs.There is a wide enough sweep voltageoutput to provide a complete pictureof the response curve of a video am-plifier (except for the lowest frequen-cies passed by the video amplifier).

Operation of the Mega -SweepA period of time should be allowed

in order for this test equipment toreach a stable state. The S weepAmplitude Control is set to its maxi-mum counter -clockwise position andthe Attenuator Control is rotatedcounter -clockwise until the springtension is released. There are twoPeaking Adjustment Controls and anassociated switch. The switch is helddown and the crystal current readingon the meter is made maximum byrotating Peaking Adjustment #2which is a reading of the conditionof Oscillator #2. With the switchstill in the down position the WaveMeter Control is rotated until a verydefinite dip is found in crystal cur-rent. This reading is an indicationof the frequency of this oscillator andshould be recorded; the switch isthen released.

Since the output signal will bedetermined by the difference in fre-quency between the two oscillatorsthis reading is very important.Oscillator #1 is set in the same man-ner as Oscillator #2 except that thewave meter is adjusted to provide adip corresponding to the desired fre-quency of Oscillator #1. Oscillator#1 is adjusted by first peaking thecrystal current reading by PeakingAdjustment #1. The Coarse Frequen-cy Adjustment is then rotated. Smallfrequency changes are made by ad-justing the Fine Frequency Control.The peaking adjustments and thecoarse and fine frequency controls areused only when it is desired to setthe Mega -Sweep in a new operatingfrequency.

Operation Procedure1. Set Sweep Amplitude Control

counter -clockwise.2. Set attenuator Control counter-

clockwise.3. With the switch in down position

rotate Peaking Adjustment #2 formaximum current reading. Rotate theWave Meter for maximum dip. Recordthis reading and release switch.

OSCILLOSCOPE( EXTERNAL SWEEP

POSITION )

Fig. 2. Operation of Mega -Sweep in block diagram form.

4. Set Wave Meter at the properposition corresponding to the desiredoutput frequency of the local oscilla-tor. Remember that the output fre-quency represents the difference be-tween the two oscillators.

5. Rotate Peaking Adjustment #1for maximum current.

6. Adjust Coarse Frequency Con-trol for a meter dip.

(Voltage should never be applied tothe output jack because of the possi-bility of damaging both the meter andthe crystal.)

7. A switch marked, 3 mc. per di-vision or 0.1 mc. per division is usedin conjunction with the Sweep ampli-tude to control the range of the fre-quency change.

In this manner the Mega -Sweepfunctions as a sweeping oscillator withtwo outputs. One output is the r -fsignal which is variable in frequencyat a rate which may be changed. Byuse of peaking adjustments and thecoarse frequency control, (and the finefrequency control if necessary) thecenter frequency of the r -f output maybe obtained. This is found to be thedifference in frequency between thetwo Klystron oscillators. The otheroutput is the sweep voltage going tothe cathode ray oscilloscope. Thesweep frequency may be adjusted byuse of the sweep rate control andthis is not a critical adjustment. Thesweep width or sweep amplitude isadjusted by means of the toggleswitch and sweep amplitude control.Thus there are three variables; thecenter frequency of the oscillator out-put signal, the sweep frequency rate,and the amount of swing over whichthe center frequency is deviated. Ingeneral use the Mega -Sweep shouldhave a 0.01 afd across the outputin order to cut down traces of un-wanted signals.

In Fig. 2 the Mega -Sweep is shownin operation in block form. The sweepoutput is feed from the Mega -Sweepinto the cathode ray oscilloscope; thisscope must have the Sweep SelectorSwitch set to external position. Thissweep voltage will pass through thehorizontal amplifier of the scope andbecome the sweep voltage of the ca-thode ray tube. The r -f voltage out-put from the Mega -Sweep is feed tothe grid of the mixer tube assumingthat we are aligning a video amplifier.The output of the video amplifier isplaced upon the vertical signal platesof the cathode ray tube. In this man-ner the signal and the sweep willbe in exact synchronization in orderto provide a visual signal on the scope.


Xigit Qliality,anattpla

Iv, I. TUTHILL

PART 1

Browning Laboratories RJ-20 FM -AM tuner

.1111111I'M in till% Slril'S on high IFII and %II ill Ill`I"%

1' II ER requirementI

high Quali f I doption in thecommercial field,

b. engineered equipment for cus-tom-built spreads,

c. precision laboratory assign-ments,

d. finger-tip control from the easy -chair,

e. rejuvenation of a cherished butantiquated cabinet, or whateverelse, the AM -FM Tuner Chassisup for discussion offers a goodexample of equipment capableof meeting that requirement.

FM Sectionof this dual tuner

(Model 1U-20 Brownie_ I

ries) is independent of du M .( d-tion. Its Armstrong circuit has itsown RF, Mixer, IF, Cascade Limiter,and Discriminator sections. Only theaudio output section is common to AMand FM. In the schematic of Fig. 1,we see that either a 300 ohm or 72ohm antenna may be coupled to thetuned r -f stage employing the minia-ture pentode 6UA6 tube. It will benoted from the schematic that fourmore of these 6UA6 miniatures areused in the FM section. Their highmutual conductance and low inter -electrode capacitance, (0.0035 iq max-imum between grid and plate) ideallyqualifies them for the functions as-signed.

R.1-20, R., -1,4,0 4.1 IC 'LINERS LI, NL 4T[EM

NICNAR4,C,5MC

iiOvNoi,

,,CCMPEKSATION 0.14),E,

IN TN STACC,,C, (441,1-' 'ION 11,6" ILL)) IN ALL10!'0)

1 !T

ELAPT.EV TIME MCASVRLD FROM15 SECONDS ArTER 'WAN ON

Fig. 2. Stabilizing effect of ceramic trimmer.

old

o5

RJ-2G,1,17A. 5 1,-, '1,11RSN001 6 A,DIC Corey?45 INPUT SIGNAL

4.f.st[D, uSt

The output of the t r -f

feeds a triode mixer Hi u- holdingmixer noise to a minimum since suchnoise is a function of the number oftube elements involved. Mixer andoscillator duties are performed by atwin triode (7F8) shown split in theschematic for reasons of clarity. Thefirst half of this tube serves the FMMixer circuit while the second triodehalf of the tube is used as a localoscillator. The curves of Fig. 2 provethe need for stability control at thispoint. It will be noted from the uppercurve, where no temperature compen-sation was employed, that the oscilla-t o r frequency drifted considerablyeven after 10 minutes of operation.The lower curve of Fig. 2 shows the

FM PERFORMANCE

rn, , 1.1,ff VT, TAP! VI °,3110.

SO 100 50,J CPO

R.F. SIGNAL INPUT -MICROVOLTS

Fig. 3. Limiter action.

1,00

1.


stabilized results through the intro-duction of a ceramic trimmer havinga temperature coefficient of -750 partsper million per CO, and through thejudicious placing of components rel-ative to heat sources. Oscillator driftis stopped, even reversed.

It can be shown that oscillator fre-quency shifts up to 20 kc are imper-ceptible and do not require tuning.The lower compensated curve of Fig.2 shows a total drift of no more than20 kc after 1 minute of operation.That much time is usually required,after the set is turned on, for the selec-tion and tuning of a desired station.Hence stability is available from theoutset. Plate voltage is fed to eitherthe FM or AM oscillator throughswitch (Sw-i).

Returning to the mixer, we findfrom the schematic that its output isfed to two tuned i-f stages employingonce again the miniature 6ITA6 tubes.These are high gain stages operatingat a frequency of 8.25 megacycles.Slightly overcoupled transformers af-ford the necessary 150 kc bandwidthwith good adjacent channel attenua-tion. High dielectric constant ceramicsare used for r -f by-passing throughoutthe amplifier.

Limiter ActionSignals pass from the i-f stages to

a cascade limiter, again employingtwo miniature 6UA6s, where ampli-tude disturbances are removed andwhere noise peaks are clipped to thesame amplitude as the limited carrier.

It is essential in any FM receiverthat an adequate signal level be ap-plied to the input of the limiter if it isto derive effective limiting action.Only then will the full qualities ofthe FM be realized in the reductionof noise and interference. For thatreason more gain is required betweenantenna and the discriminator or finaldetector than is usually required inAM tuners.

This points up the fact that a goodantenna is particularly essential, infact the orientation of a good dipolemeans the final elimination of con-tradictions in reception.

Limiter action is graphically shownin Fig. 3. Here curves are plotted ofnoise voltage and audio output versusinput signal. According to thesecurves, background noise is down 20db down when a 6.5 micro -volt signalis present on the antenna. Similarlythere is a 32 db quieting if a signalof 10 micro -volts be introduced. Re-

ception of distant or weak FM sta-tions is aided by such sensitivity.Discriminator Performance

The output of the second limiter isapplied to a balanced discriminatorcircuit which demodulates the signaland produces a useful audio voltage.In the schematic of Fig. 1 this is com-prised of the dual diode (6AL5) calleda detector and its preceding tunedcoupling circuits. It is in this circuitthat translations of frequency varia-tions to amplitude variations occur.If this is to be accomplished with trueundistorted reproduction the relationbetween frequency and output volt-age amplitude must be linear over theintermediate frequency b a n d p a s a.Measurements for this chassis indi-cate no more than 31/2% deviationfrom linearity over a range 75kc aboveand below the i-f center frequency.This represents one form of stabilitycontrol which contributes toward cleanreproduction. Tests recorded for thisequipment indicated the presence of1.06% 2nd harmonic distortion and2.65% 3rd harmonic distortion for a200 microvolt input on 100 me with400 cycle modulation and 75 kc devi-ation.

[To be continued]

COCAMI01

sum ON

AV SECTION/

rH SECTion

47.

HO.

OSCILI-Ai

tr

7

RJ-20 FM -AM TUNERBROWNING LABORATORIES, INC.

WINCHESTER, MASS. U SA.

CV

DMA

E-131?!#trit

RJ-20-1,5 7-48

1'

Fig. I. Circuit diagram of Browning Laboratories RJ-20 FM -AM tuner.


Fig. I. Physical view of Philco Aspen antenna.

TILE television industry, includ-. ing especially service techni-

cians, as well as the public have longhoped for a television receiver withan efficient and satisfactory built-inaerial. That day has now come withthe introduction of the new Philcotelevision receivers for 1950, whichincorporate an electronic built-inaerial system developed in the com-pany's research and engineering lab-oratories.

This aerial may be called electronicbecause it is electrically tunable toeach of the present 12 televisionchannels. The aerial is built in as anintegral part of all the new Philcotelevision models, including table re-ceivers, consolettes, television consolesand TV -radio -phonograph combina-tions in various sizes and styles ofcabinets.

The new built-in aerial should prop-erly be considered as a system becauseit provides not only a broad -band an-tenna, but also a tunable matchingdevice and lead-in to bring the re-ceived signal into the tuner at peakefficiency for each channel.

The result is that this Philco elec-tronic built-in aerial system, on thebasis of careful and thorough fieldtests, in a great many installations

Fig. 2. Representation of coils con-tained in Philco antenna.

PHILCO'S BUILT-IN

TV ANTENNA

The announcement of Philco's newbuilt-in antenna has aroused theinterest and curiosity of our

makes outdoor antennas unnecessary.We do not claim that this Philcobuilt-in aerial is a cure-all for everyinstallation problem. We do know thatin the vast majority of many scoresof test locations in the New York,Chicago, Philadelphia and Washing-ton areas, this new built-in aerialsystem has given good performance.

Housing The AerialThe Philco built-in aerial system

consists essentially of two parts; anantenna that covers both the low band(54-88 mc) and the high band (174-216 mc) satisfactorily; and a tunablecircuit for matching the aerial to thestandard 300 -ohm input line to thetuner.

The physical characteristics of thisaerial system are illustrated in Fig. 1.The antenna itself is a half -wave di-pole consisting of two tapered sec-tions of aluminum foil 0.005" thick.The narrow ends of these aluminumarms of the dipole are attached to atunable matching circuit consistingof a variable condenser connectedacross the terminals of a hairpin coil,which has two shorter loops attachedto it at the antenna end. The 300 -ohmline is taken off at the halfway pointof the hairpin. A simplified sketchof these coils appears in Fig. 2. Along bakelite rod with a control knobat one end is attached to the tuningcondenser, not shown in Fig. 2.

When mounted in the cabinet ofa television receiver, this Philco built-in aerial is attached to the underside of the top of the cabinet. Thealuminum foil extends across the

width of the cabinet, near the backand is folded at the wide ends notonly to follow the contours of theinside of the cabinet but also to pro-vide augumented capacity betweenthe ends of the dipole. The rod carry-ing the tuning knob extends from therear to the front, and the knob itselfappears in a special slot at the topfront of the cabinet so that it is easyfor the user to tune the aerial. Thisconstruction is shown in Figs. 3 and4.

In most of the new Philco tele-vision receivers, it is possible to re-move the chassis from the cabinetwithout disturbing the built-in aerial.In the case of two smaller table mod-els, the 1104 and 1105, the built-inaerial can readily be removed by tak-ing out two screws holding the con-denser assembly and a single setscrew at the front holding the tuningknob. This aerial should be removedbefore the chassis is taken out ofPhilco models 1104 and 1105.

Fig. 4. Front adjustment.


by JOHN PELL

Manager of Television ServicePhilco Corporation

readers. In this article the the-ory of operation and practicalservice data are made available.

New The BeW-In Aerial WorksThe simplest way to understand

the principles behind the Philcobuilt-in aerial is to examine a schem-atic of this aerial's equivalent circuit,shown in Fig. 5A. At the extremeright is the circuit of the antenna,or of the two aluminum foil sections.Note that it consists of both a re-actance, It, and the radiation resist-ance of the antenna, RA. Connectedto this antenna circuit is the tunablematching circuit, consisting of thevariable condenser with reactance Xo,the two smaller side loops which areinductive with reactances labeled Xiand X2, and the long inductive loop

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Fig. 3. View of antenna mounted in cabinet.

with reactance Xi. Note at the leftthat the 300 -ohm transmission line,which leads to the tuner and is la-beled Ti, is tapped off the long coilat a point which corresponds to animpedance of about 300 ohms. Thisobviously results in a good match be-tween the antenna (foil) and thelead-in (twin -X) to the tuner andinput circuit, and hence a minimumstanding wave ratio.

This point is graphically shown inFig. 5B, which indicates that thematching circuit connected to the an-tenna is tuned for each channel to animpedance of about 1500 ohms. Bychoosing the right point on the long

Flan SI

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loop at which to tap off the 300 -ohmline, we can effectively match theline's 300 -ohm impedance. The actualtap -off point is approximately halfwayalong the length of the long loop.

Now let us consider the matchingcircuit and equivalent antenna circuitagain, to see how they behave for thelow and high bands. Over the lowband, 54-88 me, the radiation resist-ance, RA, of the antenna is fairly uni-form and low in value. while the an-tenna's reactance, IA, is capacitiveas shown in Fig. 5C. Hence to bringthis antenna circuit to resonance fortelevision channels 2 to 6, the match-ing circuit must be inductive. Therelatively large inductance of the loopor hairpin loop is the principal factorin achieving this, whereas the effectof the smaller loops on this band isof lesser importance. The tuningcapacitor serves to vary the inductivereactance of the long loop over thelow band for the purpose of matchingthe X A (capacitive) of the antenna.

A similar analysis of the aerial sys-tem's operation on highband channelsis illustrated in Fig. 5D. Note thatnow the antenna's reactance, X A, isinductive. Also it may be mentionedthat the radiation resistance of theantenna is higher on channels '7

through 13. Here the circuit is tunedto resonance by means of the variablecondenser, and the inductance of thetwo smaller loops, Xi and X2, is asubstantial factor.

Summarizing this circuit analysis,it is evident that the Philco built-in

RADIO SERVICE DEALER:4 SEPTEMBER, 1949 21

aerial system includes an antenna,the response of which is quite goodover both high and low televisionbands, and a tunable matching circuitwhich converts the impedance of theaerial system at the tap -off point toabout 300 ohms and thus matches theimpedance of the short twin -X cableleading to the tuner.Performance Results withBuilt -In Aerial

It is particularly interesting to theservice technician to understand howefficient this Philco built-in aerial isin actual operation. Tests have beenmade to compare the efficiency of thebuilt-in aerial system with a half -wave folded dipole cut in each caseto the exact length for each channelfrom 2 to 13.

Such an array of folded dipoles, 12of them for the 12 channels, would beinconceivably awkward in an actualinstallation in a customer's home. Inthe case of channel 2, the full-lengthfolded dipole would have to have anoverall length of approximately 8.6feet!

It has been found that the Philcobuilt-in aerial approximates the bestresults one could obtain with 12separate folded dipoles, cut to theright dimensions for each station.Hence, with a simple and compactinstallation built into the televisionreceiver, the customer now gets per-formance equivalent to a whole`Christmas tree" of specially cutaerials.Servicing Information

By turning the aerial tuning knob,mounted at the top front of the cabi-

net as shown in Fig. 4, it is possible totune the Philco electronic built-inaerial system to resonance with thevideo carrier frequency of each chan-nel.

This aerial system is adjusted atthe factory so as to resonate on eachof the 12 channels at the correct tun-ing position. These tuning positionsare shown on Fig. 6, which indicatesthe fraction of a full turn counter-clockwise from the completely clock-wise position of the tuning controlneeded to reach the correct resonanceposition for each channel. For in-stance, to tune in channel 2, the knobis turned only a slight distancecounter -clockwise from the fully clock-wise position.

Incidentally, it should be noted thatall the other controls of the receiver(channel selector, fine tuning, etc.)should first be correctly adjusted forthe desired station. Then use theaerial tuning control to bring in thebest picture and sound on the de-sired channel.

As noted above in connection withthe smaller Philco table televisionreceivers, Models 1104 and 1105, it isnecessary to remove the built-in aerialbefore taking the chassis out of thecabinet. Tills aerial is readily removedby taking out the two screws at thecenter top rear of the cabinet-thesescrews holding the tuning condenserassembly in place-and by taking outthe set screw in the tuning knob atthe front of the cabinet.

When the built-in aerial is removed,it may get out of adjustment. Orthere may be other reasons why it is

IEll.POSITIONS OF TUNING KNOB OF THE PHILCO BUILT-IN AERIAL SYSTEM FORTHE 12 TELEVISION CHANNELS

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COUNTER -CLOCKWISE TURNS OF TUNING KNOB FROM COMPLETE I IIICLOCKWISE POSIT ON

FIGURE 6

Fig. 6. Knob positions for various channels.

SIGNAL DIPOLEGENERATOR

D.C. METER

ATTENUATOR KNOB

READ MAXIMUM OFONE VOLT TO PREVENTA G C ACTION

VIDEO CARRIERFREQUENCY

ASPEN ADJUSTMENT

VIDEO TESTJACK

Fig. 7. Aligning Philco antenna

necessary to adjust this Philco built-in aerial system. Any competent ser-vice technician will find the followingadjustment procedure easy to carryout. However, one point should bementioned first. In the presence ofvery strong signals, the tuning of thebuilt-in aerial will not appear to besharp because of the AGC action. Insuch cases, tune the receiver bymeans of the aerial tuning controlfor minimum background noise oneach station.

Alignment Procedure1. Connect a dipole through a 72 -

ohm coaxial cable to the output of asuitable AM signal generator havinga band range covering the televisionchannels. For instance, the PhilcoModel 7008 Precision Visual Align-ment Generator, as shown in Fig. 7,provides an efficient signal generatorfor such TV servicing. It should bementioned that the dipole used forthis purpose may be merely two clip-leads of appropriate length.

2. Connect a 20,000 -ohm -per -voltvoltmeter to the AGC bus, pin 2, ofthe Align Test Jack of the receiver.(In some early production models, pin1 is the AGO bus.)

3. Turn the Contrast Control ofthe receiver fully counter -clockwise toremove delay voltage from the AGCcircuit.

4. Set the Channel Selector toChannel 2 and the Fine Tuning Con-trol to the middle of its range. Thentune the receiver's local oscillator onthe sound carrier of the channel (tunefor maximum sound).

5. Place the dipole near the backof the receiver, and set the signalgenerator for a modulated output atthe video carrier frequency of Chan-nel 2. Adjust the signal generator at-tenuator for an output that will justgive an indication on the meter. Keepthe meter reading less than 1 voltDC.

6. Turn the Aerial Tuning Control[Continued on page 30]


General Electric 376This nine -tube, a -c d -c instrument

covers standard and FM bands. Inline with the trend to eliminate, in -so -far as possible, losses introducedby range switches, particularly elab-orate multi - section ones, use ismade of circuits which are out of theordinary. A partial schematic showsdetails to be discussed.

The input circuit of the 6AG5tuner r -f stage is fairly conventional.The grid is switched to the loop forAM and to an inductance -tuned cir-cuit for FM reception. A fixed cap-acitor across the coil completes thetuned circuit, except for the antennamatching network. Note that the an-tenna transmission line and smallcapacitor form a capacitor voltagedivider or impedance matching de-vice.

In the plate circuit of the 6AK5we find Ch,-/. This coil is series reson-ant at such a frequency that it con-fines the FM signal voltage to theplate and the 47 ittLf coupling cap-acitor. The signal appears across thesecond inductance -tuned circuit. Asmall capacitor couples the signal tothe signal grid of the 6BE6 convertorstage. Ch -2, like Ch -1 maintains thethe circuit at high impedance for FMfrequencies.

Partial schematic of FM head end of Temple 14 tube receiver, Model G-1430.

In the case of AM signals, theypass readily through the relativelylow inductance of Ch -1 and build upvoltage across the primary of the AMinterstage transformer. The seconda-ry of the transformer is tuned andtapped at an appropriate point. AMsignal voltage from this tap is im-pressed on the converter grid throughthe small inductance of Ch -2.

R -F and converter stages of G.E. 376

Note that the 47 and 10 /414 cap-acitors which couple the FM signalsbetween the r -f and converter simplyact as small shunt capacitors to thetuned grid circuit of the mixer inthe AM position.

Both 455 kc and 10.7 mc appear inthe plate series coils of the mixer andsubsequent amplification takes placein a conventional manner, with theonly switching at the secondaries ofthese transformers.

Temple Model G-1430Several features of interest are

to be found in this one instrument,a 14 tube a -c, multi -wave band set.To be discussed at this time is theFM head end. The tubes and circuitsinvolved are shown in the partialschematic. A single type 7Q7 per-forms similar functions on AM, andboth arrangements feed into a com-mon i-f system at the usual 455 kcand 10.7 mc frequencies.

Signals from a resonant dipoleantenna, built-in or external, arematched to the first coil L1, by anappropriate tap thereon. This coil isself -resonant at the middle of theFM band and applies the signal tothe grid of V1, a type 7H7, r -f am-plifier. The plate voltage for the tube



ASSOCIATIONNEWS

Empire State Federation Of Electronic Technicians Associations

TV LECTURE SERIES - SEPT. 7, 1949 TO MAY 23, 1950

1. The nature of TV, transmission and reception, modulated waveforms, high frequency propogationand reception

2. Antennas and transmission lines3. Front ends, mechanical and electrical consideration of4. Video i-f circuits of all types including intercarrier systems5. Sound circuits and alignment6. Detector and video amplifiers-theory and commercial applications including intercarrier systems7. Cathode Ray picture tubes-operation and control circuits8. Synch and sweep circuits-theory and commercial applications, adjustments and controls, AFC9. High voltage circuits-theory and commercial applications

10. Cathode ray oscilloscope-theory and applications in TV11. Cathode ray oscilloscope-theory and applications in TV12. Sweep Generators-theory and applications in conjunction with CRO13. Alignment of TV receivers-theory and practical applications14. Installation Problems, midtown, suburban, fringe areas15. Servicing TV receivers16. Examination

New York City AreaLecture No.1; Sept. 7, 1949John F. Rider Publishers, Inc.

Lecture No. 2; Sept. 21, 1949The Ward Products Corp.

Lecture No. 3; Oct. 5, 1949Philco Corp.

Lecture No. 4; Oct. 19, 1949Westinghouse Elec. Corp.

Lecture No. 5; Nov. 2, 1949Emerson Radio & Phono Corp.

Lecture No. 6; Nov. 16, 1949Radio Corp. of America &Radio Service Dealer Magazine

Lecture No. 7; Dec. 7, 1949Allen B. DuMont Labs., Inc.

Lecture No. 8; Jan. 4, 1950Bendix Radio

Lecture No. 9; Jari. 18, 1950Beta Electronics Co.

Lecture No. 10; Feb. 1, 1950The Hickok Electrical Instrument Co.

Lecture No. 11; Feb. 15, 1950Allen B. DuMont Labs., Inc.

Lecture No. 12; Mar. 1, 1950Coastwise Electronics Co.

Lecture No. 13; Mar. 15, 1950Kay Electric Co.

Lecture No. 14; Apr. 5, 1950Service Magazine

Lecture No. 15; Apr. 19, 1950Allen B. DuMont Labs., Inc.

Lecture No. 16; May 3, 1950Examination

Poughkeepsie Area

Lecture No. 1;- Sept. 14, 1949John F. Rider Publishers, Inc.

Lecture No. 2; Sept. 28, 1949The Ward Products


Lecture No. 4; Oct. 26, 1949Westinghouse Elec. Corp.


Lecture No. 6; Nov. 23, 1949Radio Corp. of America &Radio Service Dealer Magazine

Lecture No. 7; Dec. 14, 1949Allen B. DuMont Labs., Inc.

Lecture No. 8; Jan. 11, 1950Bendix Radio

Lecture No. 9; Jan. 25, 1930Beta Electronics Co.


Lecture No. 11; Feb. 22, 1950Allen B. DuMont Labs., Inc.


24 "'RADIO. SERVICE DIALER SEPTEMBER, 1949

NEW PRODUCTS

TV BOOSTERA new television booster declared to provide

high gain is announced by The Astat'c Cor-poration, Conneaut, Ohio, representing theinitial entry into the television field of thiswell known manufacturer.

HORIZONTAL OSC. COILThe new horizontal -oscillator and sync -

stabilizer coil 203R2 is designed for use intelevision receivers employing the medium -mutwin triode 6SN7-GT as a combined horizontalblocking -oscillator and synhcronizing-c,,ntroltube. The synchronizing control coilimproves the stability of the horizontal -cil-Bor. Tube Department, Radio Corp. of k men --

ca, Harrison, N. J.

TV TOWERSBaker Manufacturing Company, Evansville,

Wisconsin, announces a newly designed line ofMonitor Towers for Television. Models includedin the line are guyed ground and roof mount-ing towers and a three post self supoortingtower, all of steel construction.

MIDGET -CAN ELECTROLYTICSThe insulation of terminals and leads, added

to the stud terminal construction previouslyannounced, round- out the advanced designof the new Typt PRS multi -section Dandeesor midget -can electrolytics offered by AerovoxCorporation, New Bedford, Mass.

SWEEP GENERATORA new entirely electronic sweep generator,

Type ST -4A using a variable permeabilitytype sweep and having no moving compo-nents has been developed by the SpecialtyDivision of the General Electric Company atElectronics Park, Syracuse, N. Y.

ANTENNA ROTATORRadiant Corporation of Cleveland, Ohio, an-

nounces the Radiart Tele-Rotor. This newrotator rotates the antenna to the exact pointthat affords the clearest reception and simul-taneously indicates the position of the antennaby lights on the remote -control unit that ismounted in an attractive brown plastic cab-inet.

16 INCH TUBESylvania 16 inch metal direct view television

tubes are now available for authorized dis-tributors. Advantages of the metal tube, ac-cording to Sylvania, include increased physicalstrength, a reduction in weight of approx-imately 50%, increased image brightness andimproved contrast of television image, a rela-tively flat face and ion trap gun.

TV ANTENNAThe Dielectric Products Company, Inc. of

Jersey City, New Jersey, announces the avail-ability of its DPC Duoband Dipole with Re-flectors featuring the Exclusive Duo -AntennaHead.

TV ANTENNAThe Ward Products Corp., a division of the

Gabriel Co., 1523 E. 45th St., Cleveland 3,

Ohio, has announced its new, Model TVS-47television antenna which reduces installationtime and cost considerably.


Association NewsRACON LOUDSPEAKERS . . . America's Finest Since 1922

LITY"There is hardly anything in the world thatsome ?non cannot make a little worse and sella little cheaper . . . and the people who con-sider price only are this man's lawful prey."

-RUSKIN

Pretty smart chap, this Ruskin.

Styles may have changed since his time, but basic thinking remainsthe same. There are still many of us who believe the best is the leastexpensive in the long run and will not accept any shortcuts to quality.

Racon Electric Co., Inc., was founded twenty-seven years ago with theclear conviction of the kind of products to make . . . the best publicaddress loudspeakers it was in their power to produce, without anycompromise to accepted acoustical theory or craftsman's honor.

Today, Racon has not only a national but an international reputationfor quality. Users of Racon loudspeakers range from industrial, marineand railroad companies to educational institutions and U.S. and foreigngovernment agencies.

Where specifications call for the finest loudspeaker, you will find thatsooner or later, they gravitate to Racon.

All Racon products are guaranteed for 18 months.

SOUND TECHNICIANS AND SERVICEMEN - For lull details on ourcomplete line of Public Address and Wide Range Loudspeakers, see yourfavorite parts jobber, or write for Catalog D.

SoundEquipment

Manufacturers

52 East 19 St.New York 3,

N. Y.

Symbol of Acoustical Excellence Since 1922

[from page 241

Lecture No. 12; Mar. S, 1950Coastwise Electronics

Lecture No. 13; Mar. 22, 1950Kay Electric Co.


Lecture No. 15; Apr. 26, 1950Allen B. DuMont Labs., Inc.


Binghamton -Endicott Area

Lecture No. 1; Sept. 21, 1949John F. Rider Publishers, Inc.

Lecture No. 2; Oct. 5, 1949The Ward Products Corp.


Lecture No. 4; Nov. 2, 1949Westinghouse Elec. Corp.


Lecture No. 6; Dec. 7, 1949Radio Corp. of America &Radio Service Dealer Magazine

Lecture No. 7; Jan. 4, 1950Allen B. DuMont Labs., Inc.

Lecture No. 8; Jan. IS, 1950Motorola Inc.

Lecture No. 9; Feb. 1, 1950Precision Apparatus Co., Inc.


Lecture No. 11; Mar. 1, 1930Allen B. DuMont Labs., Inc.

Lecture No. 12; Mar. 15, 1950General Electric Co.

Lecture No. 13; Apr. 5, 1950Kay Electric Co.


Lecture No. 15; May 3, 1950Allen B. DuMont Labs., Inc.




Here are some of the many reasonswhy there are more Simpson 260 high

sensitivity volt-ohm-milliammetersin use today than all others combined. The

Simpson 260 has earned world-wideacceptance because it was the first tester

of its kind with all these "Firsts":

440A

400 VA A.1E80 °A"5

400

RN. t

R%100

RXI0.00°

260 SET TESTERWORLD FAMOUS FOR ALL THESE "FIRSTS"

First high sensitivity instrument to use a metal armature frame. First to use fully enclosed dust proof rotary switch with all contacts

molded in place accurately and firmly.

First to do away with harness wiring. First to provide separate molded recesses for resistors, batteries, etc. First to cover all resistors to prevent shorts and accidental damage

and to protect against dust and dirt. First with a sturdy movement adapted to the rugged requirements

of a wide range of service work or laboratory testing. First to provide easy means of replacing batteries. First to use all bakelite case and panels in volt-ohm-milliammeters. First volt-ohm-milliammeter at 20,000 ohms per volt with large 41/z"

meter supplied in compact case (size 51/4"x 7"x 31/8").

First and only one available with Simpson patented Roll Top Case. First to provide convenient compartment for test leads (Roll Top

case).

First to offer choice of colors.

The Model 260 also is available in the famous patented Roll Top safety case withbuilt-in lead compartment. This sturdy, molded, bakelite case with Roll Top providesmaximum protection for your 260 when used for servicing in the field or shop.

25,000 volt DC Probe for television servicing, complete, for use with 260, $12.85

SIMPSON ELECTRIC COMPANY 5200-18 W. Kinzie St., Chicago 44, III. In Canada: Bach -Simpson, Ltd., London, Ont._.

RANGES20,000 Ohms per Volt DC, 1,000Ohms per Volt ACVOLTS: AC & DC -2.5, 10, 50, 250,1,000, 5,000OUTPUT: 2.5, 10, 50, 250, 1000MILLIAMPERES, DC: 10, 100, 500MICROAMPERES, DC: 100AMPERES, DC: 10DECIBELS: (5 ranges) -12 to +55 DBOHMS: 0.2,000 (12 ohms center),0-200,000 (1200 ohms center), 0-20megohms (120,000 ohms center).

Prices: $38.95 dealers net; RollTop $45.95 dealers net.


Association News[from page 26]

Rochester AreaLecture No. 1; Sept. 27, 1949John F. Rider Publishers, Inc.

Lecture No. 2; Oct. 11, 1949The Ward Products Corp.Lecture No. 3; Oct. 25, 1949Philco Corp.

Lecture No. 4; Nov. 8, 1949Westinghouse Elec. Corp.

AUDIO GE',$3415°KIT

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Oka norig 114ifam Wool for .44 rood be embed:..wai..101end .rd °veered Ur.* Sta.. 11.ISO j 0.11011. V/04. ewe. 110Y 00 ewlofrom...armee 1 1on.11.1.orl. on %At..

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Lecture No. 6; Dec. 13, 1949Radio Corp. of America &Radio Service Dealer Magazine

Lecture No. 7; Jan. 10, 1950Allen B. DuMont Labs., Inc.

Lecture No. 8; Jan. 24, 1950Motorola Inc.

Lecture No. 9; Feb. 14, 1950Precision Apparatus Co., Inc.


Lecture No. 11; Mar. 14, 1950Allen B. DuMont Labs., Inc.

Lecture No. 12; Mar. 28, 1950General Electric Co.

Lecture No. 13; Apr. 11, 1950Kay Electric Co.


Lecture No. 15; May 9, 1950Allen B. DuMont Labs., Inc.


Phila. Radio Service Men'sAssociation, Inc.

On May 17th, the Philadelphia Ra-dio Service Men's Association pre-sented to its members at a closedmeeting a Television Trouble Shoot-ing Session on Zenith TV setsthrough the cooperation of MotorParts Company, who presented Mr.Jack Hirst, Television Service Mana-ger. Mr. Jack Hirst, who has had agreat many years of experience in theradio field, spent several hours ex-plaining and demonstrating the prop-er procedures for setting up, aligningand trouble shooting on Zenith tele-vision sets. He was assisted by Mr.John T. Stinson, our local Hickocktest equipment representative whohelped in demonstrating to the menpresent the proper procedure to useHickock equipment for aligning andtrouble shooting. Mr. Hirst also pro-vided sub -assemblies for the men toexamine the chassis in order, to havea better understanding of each part.

Harry Small borrowed one of DaveKrantz's ladders for TV installationand broke one of the lower wings.Harry claims that he only' fell' acouple of feet but Dave was sore and

28 RADIO SERVICE bEALEk' SEPTEMBER,- 1949

wished it was one of the top rungsthat had broken.

The Preventative Radio Mainten-ance Month.which is promoted by theState Federation for October, will besponsored under the auspices of thePRSMA here in Philadelphia. Wehave received the cooperation of allour local distributors and many ofthe members of the Keystone Chapterand at this writing, we are also ex-pecting the cooperation from all localAM and FM broadcasters and ourlocal "reps" organization, and Mr.Sam MacDonald, who is president,has assured us of such.

Mr. Jimmy Skinner, Jr., vice presi-dent in charge of Philco Service andParts, has offered us the assistanceof Bill J. Nagy who is PromotionManager for the Service Division. Wewere proud to accept this assistance.Mr. John Rider of Rider Publica-tions, Sam Marshall of Radio ServiceDealer Magazine, and Lew Winmer,editor of Service Magazine, will actas co-ordinators for the Penna. StateFederation.

From time to time you continu-ously read of theft of radio sets andappliances from stores and windowsof many dealers. Recently the follow-ing merchandise was removed fromF. C. Haab and Company, 21st andChestnut Streets:

RCA Model go.54B5 34698x542 621178B41 21858x521 10912

Independent Radio TelevisionTechnicians of Westchester County

This new association was startedon June 17, 1949. Officers are as fol-lows: Pres: Harry Weigand; V.P. :

T. Olsen; Treas. : Miles Michaelson;Sec. : M. Erler. At a meeting heldat Turn Hall, 10th and Stevens Ayes.,in Mount Vernon a substantial num-ber of men attended.

Lackawanna Radio TechniciansAssociation, Pennsylvania

The Lackawanna group has goneon record as favoring state licensingof radio and television technicians.They have expressed considerable con-cern over the safety hazards createdby the erection of some TV and FMantennas. Furthermore, the groupcontends, licensing would maintainhigh standards and ethics in the pro-fession.

With regard to Sandy Cowan's talkdelivered before the group, they say,"-personal thanks to you for yourefforts in not only giving the boysa good lecture but taking on the jobof entertainer until that darn picturemachine arrived-"

Long Beach. Radio TechniciansAssociation, Inc., Long Beach, Calif.

First June meeting featured JackMeyers and A. B. Sherwood of G:E. who talked on a new TV synccircuit. Second meeting found AlfredDowers of A. W. Marsh Co. expound-ing on changers.

Santa Monica and Los Angeles haveasked to join RTA of Long Beach.

Harry E. Ward, Chairman oftechnicians apprenticeship committeeMooney award from Carleton E.Webb, representative of the Bureauof Apprenticeship standards, U. S.Dept. of Labor. The award came when

technicians apprenticeship committeevote Mr. Ward the "Most out stand-ing, agressive and valued member" inthe Long Beach and Harbor area forthe past year.

Cooperating Appliance DealersAssociation of Brooklyn, Inc.

The Cooperating Appliance DealersAssociation of Brooklyn held theirannual informal Outing and Picnicon Sunday 24 July 1949 at the Groveand Recreation Hall in HecksherState Park.

Joseph J. JonesChairman Picnic Com.

TELEVISION Service Shops . . .

End 'Fixed' Antenna Troubles!TENNA - ROTOR

allianceFewer Call - Backs !Happier Customers !Faster Installations !Bigger Profits !

Rotator unit-metal enclosed-- moisturesealed. Size7" x 8".

Plastic control caseplugs into 110 volts.)))))-) -Size 5" = 5".

Tenna-Rotor speeds TV installations-saves man-hours on thejob because it eliminates critical antenna orientation! Now, oneman does all the work-easily and quickly! In fringe or multi -stationareas, your customers get "peak" reception, selectivity and widerrange! And it overcomes "ghosts" and variable reflection factors!Foolproof, weatherproof, built for long life, Tenna-Rotor comesindividually boxed-complete assembly (rotator and control case)-weighs 12 lbs.-retails at $39.95 (slightly higher west of Rockies).Be sure to ask for genuine Alliance 4 -conductor cable with eachunit! Join the trend to Tenna-Rotor! It pays off with more salesand faster service! Order from your jobber-NOW!

alliance motorsAlliance Manufacturing Company Alliance, OhioExport Department: '401 Broadway, New York, N.Y., U.S.A.


3 GRE

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NOW a full line of Titone's amazingceramic pick ups-made by famousSonotone! All with these great basicfeatures: Full freuency resnsefrom 50 to 10,000 q cycles.)( Bell-polikesupertone 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!

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CIRCUIT COURT[from page 28]

flows through a 4700 ohm resistor,and the screen is fed from the platevia an additional 10K unit.

The r -f voltage appearing on theplate passes thorugh a 100 Atif capaci-tor to an unusual tuned network inthe signal grid of V2, a 6SB7 penta-grid converter. L2 is a choke coilproviding return to ground for d -cpurposes and along with shunt cap-acitors determining the low frequencycharacteristics of the circuit. Theunit marked P is the adjustment forthis end of the range.

The coil L3 is the actual tuningcoil, and in conjunction with thetuning condenser and its associatedtrimmer, comprises a series -tunedresonant circuit. The use of seriestuning permits the use of largervalues of L and C with attendantimprovement in stability and gain.

V2 serves only as a mixer, havingthe oscillator voltage supplied to it'sinjection grid from a separate sourceconsisting of a 7A4 tube, V3, andappropriate components. A Colpittscircuit is employed in the oscillator.

ASPEN[from page 22]

of the receiver for a maximum read-ing on the voltmeter. For Channel 2,this maximum reading should occurless than one -quarter turn counter-clockwise from the fully clockwiseposition of the tuning knob, as shownin Fig. 6.

7. Repeat the above steps for Chan-nels 3 through 13. In each case, thepeak reading on the voltmeter shouldcome near the correct turn positionof the tuning control indicated onFig. 6.

In the event peaking cannot be ob-tained on Channel 6 in early produc-tion sets of the smaller Philco tablemodels 1104 and 1105, remove about1.5 inches of the aluminum antennafoil from the right-hand end of thefoil, looking at the rear of the cabinet.Just cut off the foil with a sharpknife and straight edge. This is theend of the foil nearest the high volt-age power supply. The uncut di-pole is level with the top of the highvoltage cage. There will be a space of11/2" when the dipole has been cut.

8. If a peak reading cannot be ob-tained on each channel in the low -frequency band at approximately thecorrect turn position of the tuning

COMPARE

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ANCHORTV - PRE - AMPLIFIER

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The ANCHOR PRE -AMPLIFIER is engi-neered to amplify the signal only, not thenoise. Furthermore, the inherent noise ofthis unit is not measurable.

The ANCHOR Booster provides maximumgains possible from the 6AK5 tube withexcellent band widths.It increases signal strength without loss ofpicture detail.The outstanding acceptance of the AN-CHOR TV -PRE -AMPLIFIER by Service En-gineers and Dealers is the best testimonialto its quality.

Engineered for modern and the best TVreception. Priced right for profits. Get de-tails now.

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NCHOR ANCHORRADIO CORP

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$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.


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knob, the long section of the loopassembly, to which the 300 -ohm lineis attached, may be pushed togetheror bowed out to obtain peaking. Re-ferring back to Figure 2, the legs ofthe loop sections labeled "A" and "B"can readily be squeezed together orpulled apart to achieve peaking in thecorrect turn position for each low -band channel from 2 to 6.

9. If a peak reading cannot be ob-tained on each channel in the high -frequency television band, the twosmall loops near the tuning con-denser (marked "C" in Fig. 2) maybe elongated by squeezing the wirestogether or may be bowed out intomore circular shape.

After these adjustments have beenmade, if it is still not possible to ob-tain maximum meter readings at thecorrect positions of the Aerial TuningControl, we suggest that the variabletuning condenser be replaced. Inci-dentally, this aerial tuning capacitorhas a capacitance range from 2 to30 /LILL

Life Testing of PhileoThe new Philco electronic built-in

aerial system was developed, designedand engineered for production over aconsiderable period of time, as youmay imagine. An important phase ofengineering this aerial system forproduction was to take the originalmodels, developed by a group fromthe Research Division and Engineer-ing Department under the directionof Robert B. Albright, and to subjectthese models to grueling life tests.

During the life tests, a number ofminor flaws in the construction of themoving parts of the aerial tuning as-sembly were discovered and corrected.Production samples of the new Philcobuilt-in aerial system have been testedon a special machine which turns theknob of the tuning assembly throughits entire throw, from tight clockwiseto fully counter -clockwise. A typicalPhilco aerial is still in good conditionafter 45,000 turns or the equivalentof many years' service in the custo-mer's home.Field Tests

As we have seen, tests of the Philcotunable built-in aerial shows that theperformance of this new system issubstantially equivalent to that of adozen folded dipoles, each cut to pre-cisely the right length for each of the12 television channels.

These results have been corrobor-ated by a series of extensive field en-gineering tests of the Philco elec-tronic built-in aerial in four metro-politan areas: New York, Philadel-phia, Chicago and Washington.

In the heart of Manhattan's mid-town skyscraper region, where good

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reception is difficult, surprisinglygood performance has been obtainedfrom the Philco built-in aerial. Inaddition, a comparison of receptionwas made from a new Philco receiverwith a built-in aerial system vs. re-ception from an identical receiverwhich had its built-in areial purpose-ly disconnected and was instead con-nected to a good outside antenna. Theresults of these tests indicated that,in the presence of a fair -to -strongsignal, the reception from the built-in aerial was superior in quality! Thisis because, using the tunable built-inaerial, a better match was obtainedon each channel and it was possibleto tune out interference from FM sta-tions and other electrical noise.

Such tests, made in a wide varietyof locations by Philco field engineers,proved that the new electronic built-in aerial will be valuable to manyoccupants of metropolitan apartmentbuildings and hotels, especially wherelandlords have refused permission forrooftop aerials.

Even more successful results in re-ception were obtained when the Phil -co built-in aerial system was testedin residential districts around Man-hattan, including Queens, Flushing,Brooklyn, The Bronx, northern NewJersey and the commuting areas ofLong Island and Westchester County.Here good picture and sound qualitywas obtained from practically all sta-tions an all locations.

In Philadelphia and Chicago, simi-lar tests indicated comparable per-formance. In the downtown areaswhere there are tall buildings, recep-tion is often marred by multipleimages, but performance with thisbuilt-in aerial was superior to thatwith a typical single dipole outdoorantenna. Tests made in the residentialdistricts of these cities indicated ex-cellent reception in the vast majorityof locations.

Tests made at a great many sitesthroughout the Washington, D. C.area showed that up to 80% of pros-pective customers will get good recep-tion with the Philco electronic built-in aerial system. In Washington, thetransmitters are located favorably andthere are few tall buildings-condi-tions typical of many other televisioncities. Here it can safely be said that"plug -in -and -play" performance intelevision has arrived with the Philcotunable built-in aerial system.

One final point should be noted. Infringe locations, where the signal isvery weak, an outdoor antenna maybe necessary. In such cases, discon-nect the built-in aerial merely by re-moving its 300 -ohm line from theantenna terminals and then substitutethe lead-in from the outside aerial.

AD INDEX

Alliance Manufacturing Co 29Allied Radio Corp 32American Phenolic Corp 2

American Television & Radio Co 31

Anchor Radio Corp 30

Belden Manufacturing Co 5

Bogen Co., Inc., David 32

Commercial Trades Institute 32

General Electric Co. (Tube Div.)....I3

Heath Company 28Hytron Radio & Elec. Corp Cover 3

Industrial Condenser Corp 28International Resistance Co 8, 9

Mallory & Co. Inc., P. R Cover 2Merit Coil & Transformer Corp 31

Permoflux Corp 3

Racon Electric Co., Inc 26Radiart Corporation, The II

RCA -Victor (Test Equip. Div.) 6RCA -Victor (Tube Div.) Cover 4

Sams & Co., Inc., Howard W 7Shure Brothers, Inc 10

Simpson Elec. Co 27Sonotone Corp 30South River Metal Products Co 32Sprague Products Co 4Sylvania Elec. Prods., Inc 14

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Solve your man -power shortage by employing well -trained, dependable young menwhe have beentrained by Commercial Trades Institute. Ourgraduates have completed an intensive course InRadio or Television Servicing. Their training hasbeen practical-in well-equipped shops under ex.pert supervision. They've learned to de 11E0111055work. To enable you to evaluate the 'Moloney ofC.T.I. training, we'll be glad to send you anoutline of the course. You'll end the subject mat-ter extensive, complete, THOROUGH.We probably have men who hail from your vicinity,but moat of our graduates will travel anywherefor a good opportunity. We cordially Invite em-ployers to write us for detailed Information enavailable men. (No employment fees). Address:

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TUBE LIFTER

54

THE FOUNTAINHEAD OF MODERN TUBE DEVELOPMENT IS RCA

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RCA has all the popular type tele-vision picture tubes to meet yourpresent and future renewal require-ments. And you can get them fromone dependable source ... your RCATube Distributor.

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NOW . . TV MOLINA SHOOTING STPICTURE ANC.LYSIS! Another RCA Firstin servicing aids . . . the Pict -O -Guidetells at a glance where to look for troublein a TV receiver-and indicates how tocure it. To learn how you can get yourcopy, see your RCA Tube distributorwithout delay! The supply is limited.

RAD/0 CORPORATION of AMERICAELECTRON TUBES HARRISON, N.J.

IN THIS ISSUE - americanradiohistory.com in this issue. This second scoop is ... will not be doomed...

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