A HOWARD W. SAMS PUBLICATION DECEMBER 1963 75c

SPECIAL FM STEREO ISSUE

Five feature articles on stereo broadcasting subjects: Installation, Monitoring, Antennas,

Phase Checking, and State -of -Art

Plus - Subject Reference Index, 1963 Broadcast Engineering

the technical journal of the broadcast - communications industry

www.americanradiohistory.com GATES OFFERS MOST TOTAL PACKAGE COMPLETE FM STEREO CONCEPT ASSURES PACKAGE IN INDUSTRY

MAXIMUM STEREO 1 Gates Cycloid FM Antenna - Designed PERFORMANCE for Stereo

2 Complete Line of FM A complete FM stereo broadcast Stereo Transmitters - from 10 Watts to package - specially engineered to deliver the greatest stereo realism 20,000 Watts possible - is now available from 2 the Gates Radio Company. 3 Gates M -6146 Stereo This exclusive system features a Generator full power range of stereo trans- Gates M -6160 Sub - mitters from 10 watts to 20,000 carrier Generator 67 watts, the new Cycloid antenna with KC or 41 KC. Switch- one through sixteen bays, a dual ing Kit Optional peak limiter, stereo Cartritape, the choice of two stereo audio consoles 4 Gates M -6144 Stereo and two professional stereo turn- Dual Limiter tables (12 or 16- inch) -plus other important accessories that add real- istic depth and separation to broad- cast sound. All equipment in the package was fl fl -. 5 Gates M -6158 Ex- researched, designed and manufac- a341110 o alQ® ecutive transistor tured after the FCC rules and Veto console -10- channel regulations concerning FM stereo stereo were finalized - yet each product has been extensively field tested. To assure maximum stereo per- formance, the new FM station will 6 Gates M -6188 Stereo want a fully integrated system de- Yard signed specifically for stereo -and Gates is the only manufacturer in the broadcast industry to offer such a complete equipment plan. This total package concept solves the broadcaster's problem of purchas- 7 Gates Stereo ing equipment from several different Cartritape II sources - which could result in .- an incompatible stereo broadcast rr system. Many FM stereo stations already .t,p 8 Gates M -6169 Stereo on the air may find that they are Transistor Pre- not getting full stereo performance amplifier due to an incomplete system. By reviewing the package diagram on the right, they can determine the equipment needed to assure true Gates is the only manufacturer And the mon- in the broadcast industry 9 Gates CB -500 16- stereo transmission. to offer inch aural station should investigate to such a complete stereo system. & CB -77 12- inch, with GE VR- see how relatively simple and inex- For complete information, write 1000 Gray 208S it is to convert to the "won- pensive for the FM Stereo Fact File - Stereo Cartridge world of stereo" with the derful yours for the asking. Arm complete Gates package. & Rest Full technical information on this special FM stereo package is now GATES RADIO COMPANY available. Write Gates Radio Com- (GATES Subsidiary of Harris -In tenype Corporation pany, Quincy, Ill., for the FM Stereo QUINCY ILLINOIS =1=13 Fact File. Offices in: HOUSTON, NEW YORK, LOS ANGELES, WASHINGTON, D.G. In Canada: CANADIAN MAFCONI COMPANY (Advertisement) Export Soles: ROCKE INTERNATIONAL CORP. 13 EAST 40th ST. NEW YORK CITY

Circle Item 1 on Tech Dala Card

www.americanradiohistory.com Every TV Station Doesn't Use Belden Wire and Cable .. but most of them do!

like WBAL-TV WGN -TV KIRK-TV BALTIMORE CHICAGO HOUSTON In their rev, $2,000,000 stuc o building. Behan In this mammoth newMid -America The exclusive use o1 Belden Canera, Audic, Carrera, and Contra Cales were u3-id TV and radio broadcasting center, Audio, r.nd Control Cibles by this .IBC exc usine y. 90% of all Camera, Microphone, affiliate lelpst emtomaintaintheirron- and Audio Cables are Belden. -fnuous, highly efficient programin a.

The extensive use of Be'den viire and cable by radio and television stations reflects the engineered qual- ity of all Belden wire and cable. It offers lighter weight, lower coefficient of friction, greater flexi- bility, easier termiration, and e>.clusive Beldf:il' insulations for elimiration of crosstalk.

Belden manufacturers a complete line of wire and

power supply cords cord sets and portable cord- cable for all TV and radio broadcasting, recording age magnot wire lead wire automotive wire and studios, remote control circuits, and similar applica- cable aircraft wires welding cable Belden tions. Call your Belden electronic distributor, or Better Built- Better Buy -Belden RRRRR 20111 INDUSTRY SING. 1002 - CHICAGO write for catalog. Belden Trademark -ße5. U.S. Pat. Off. $.63 BELDEN MANUFACTURING COMPANY 415 South Kilpatrick Chicago, Illinois 60644

Circle noon 2 on Tech Data Card

December. 1963 3

www.americanradiohistory.com the technical journal of the broadcast- communications industry

- first choice 'Broadcast Engineering of those who ..::..::..... demand the best! Volume 5, No. 12 December, 1963 CONTENTS ESPECIALLY DESIGNED FOR FEATURES Planning the FM Stereo Installation 8 by George W. Yazell - Points to consider in selecting STEREO FM equipment for a stereo station.

BROADCASTING Monitoring and Measuring the FM Stereo Broadcast . . 10 by Ridgely Bolgiano - Three methods for measuring the THE CROWN 822 is a precision FCC -approved stereo signal with an oscilloscope. 2 -track recorder that answers the When the Proof prime requisites for FM stereo -of- Performance Fails 12 broadcasting... (1) dependable, by Ed Murdoch - Part Four. Troubleshooting distortion and balance in push -pull stages, maintenance -free operation; (2) complete fidelity of reproduction. Antennas for FM Stereo 16 Technical Talks Stereo transmitting antenna requirements In addition, the Crown 822 is - and how to meet them. ideal for program composition be- cause of its extreme flexibility - Phase Checking of Audio Channels 18 3 speeds, 4 mixing inputs (high or by Harry A. Etkin - Practical techniques for checking the low level), separate bass /treble relative phase of channels in a stereo system. controls, adjustable echo, no FM Stereo - Past, Present and Future 20 cross -talk, Micro Touch elec- by Harold W. Kassens -A brief look at the history, current tronic operator controls, remote status, and the potential of FM Stereo. facility, cue switch, magnetic brakes (no adjusting), photo -elec- Subject Reference Index, 1963 26 tric cell automatic stop, and many Listings, by subject, month, and page, of the feature articles and items have this year. others...including individual per- that appeared formance guarantee.

Built by American craftsmen and DEPARTMENTS engineers using American com- About the Cover 6 Book Reviews 37 ponents.Write for further informa- Engineers' Exchange 22 Advertisers' Index 38 tion and /or demonstration in your News of the Industry 30 Classified Ads 38 studios. New Products 33 Engineers' Tech Data 36 Professional Services 38

THE HALLMARK OF CROWN - PUBLISHER: Howard W. Sams GENERAL MANAGER: Mal Parks, Jr. SUPERLATIVE EDITORIAL: Exec. Editor, Verne M. Ray; Editor, Forest H. Belt; Managing Editor. Stuat N. Soll; CRAFTSMANSHIP Consulting Editor, John H. Bettison. THROUGHOUT! CIRCULATION: Manager, J. A. Vitt; Fulfillment: Manager, Pat Tidd; Assistants, Katherina Kris. and Cora LaVon Willard. PRODUCTION: Manager, Robert N. Rippy. ADVERTISING: Sales Manager, Dave L. Milling; EAST: Howard W. Sams á Company, Incorporated, 3 West 57th Street, New York, N. Y., Phone -MU 8 -6350; MIDWEST -Hugh Wallace, Howard INDIVIDUAL PERFORMANCE W. Sams & Co. Inc., 4300 West 62nd Street, Indianapolis 6, Ind., Phone AX 1 -3100; SOUTHWEST - C. H. Stockwell Co., 4916 West 64th Street, Mission, Kansas, Phone -RA 2.4417; LOS ANGELES 57, OF EACH CROWN IS CALIF., Maurice A. Kimball Co., Inc., 2550 Beverly Blvd., Phone -DU- 8.6178; SAN FRANCISCO, Maurice A. Kimball Co., Inc., 580 Market Street, Phone -EX 2 -3365; PARIS 5, FRANCE, John Ash - CERTIFIED AND GUARANTEED craft, 9 Rue Lagrange, Phone -ODeon 20.87; LONDON W.C. 2, ENGLAND, John Ashcraft, 12 Bear Street, Leicester Square, Phone -WHitehall 0525; TOKYO, JAPAN, International Media Representa- tives, Ltd., Kisha Kurabu 14, 2 -chome Marunouchi, Phone -15021 0656. WRITE DEPT. BE -l2 SUBSCRIPTION PRICE: U.S. $6.00. one year; $10.00, two years; $13.00, three years. Outside U.S.A. add $1.00 per year for postage. Single copies, 75 cents, Back issues, 51.00. BROADCAST ENGINEERING Is published monthly by Technical Publications, Inc., an affiliate of Howard W. Sams & Company, Inc. Editorial, Circulation. and Advertising headquarters: 4300 © 1963 by Sams & Co., Inc. V I N T E R N A T I O West 62nd Street, Indianapolis 6, Ind. Copyright Howard W. N A L -1718 Mishawaka Rd. Elkhart, Ind. Q A HOWARD W. SAMS PUBLICATION CIreb Item 3 ea Tees Data Card 4 BROADCAST ENGINEERING

www.americanradiohistory.com Well behaved transmitters DON'T SHOUT

DON'T WHISPER!

a.a.T.. tir ..,.T.,. ,.v., ....o, CS, LASOP70M Stay listenable with Audimax!

Undulating audio is not listenable! is the Audimax Gain Platform. Audio lizer to recognize noise and back- When it shouts -unpleasantness! output remains on a natural listening ground effects, and electronics takes When it whispers- strain! Every time keel at maximum modulation. There's over. Proper levels are maintained; your listener touches his volume con - no distortion, compression, thumping gain is held constant during pauses or tro, you stand a chance of losing him! or pumping. No audio "holes." Audi - returned to normal at standby -auto- Audimax -the monitor with a memory max is not a Compressor, Limiter or matically. To get listener loyalty -and -rides your output gain control with AGC. Audimax is a control computer, keep it -you need Audimax! It pays! super -human speed. When levels are complete with memory and judgement. correct, gain remains constant -this You merely set the Gated Gain Stabi- Bs LABORATORIES A Division of Columbia Broadcasting System, Inc. Circle Item 4 on Tech Data Card December, 1963 5

www.americanradiohistory.com ABOUT THE COVER

Superb quality... moderately priced .. the preferred choice on five continents SPOTMASTER 500A At 12:00 o'clock A.M., on the morn- ing of June 1, 1961, (the earliest time authorized by the FCC), Zenith Radio Corporation's FM Station, WEFM, Chi- cago, transmitted the first stereophonic TAPE CARTRIDGE SYSTEMS FM broadcast using the new FCC stand- ards. WEFM's stereo transmitting instal- ... NOW FEATURING DELAYED PROGRAMMING lation is shown on the cover. Since that broadcast, well over 200 FM stations have begun stereo operation. Meanwhile, in a constant effort to im- prove stereophonic broadcasting, manu- facturers. stations, professional organiza- tions, and other interested groups con- tinue intensive research and experimenta- tion programs. (See FM Stereo - Past, Present, and Future, page 20.) The FM stereophonic broadcasting system tested by Zenith Radio Corp. during 1959 and 1960, and later pro- posed by Zenith and General Electric Co., was adopted officially by the FCC 500.4 complete record "playback unit 505A- playback unit on April 20, 1961. It has since been proven to be an effective and workable technique. In the lower accompanying photo is the equipment used by Zenith to demon- The new SPOTMASTER 500A interviews and other live origina- strate stereo transmission at the first in- series of tape cartridge equipment tions while the program is on the dustry showing. This took place May. is winning praise and acceptance air. The 500 A -DL may also be throughout the world. These rugged, used to meet many other delayed 1961. in Washington, D.C.. during the dependable machines provide snap - programming requirements. With National Assoc;ation of Broadcasters in cartridge loading, and split - the DL function switched off, the convention. second, one -hand operation . unit operates as a standard 500A The new stereophonic service has combined with high quality, wide recorder /playback. made steady progress since its introduc- range reproduction and all the time - tested, field- proven SPOTMASTER On five continents, more stations tion less than three years ago. In the features. use more SPOTMASTERS than words of Zenith president Joseph S. any other cartridge tape system. . a new dimension in And now something more has Write or phone for full information; Wright, it is ".. been added -the optional SPOT - learn about the SPOTMASTER FM broadcasting, and a new era for the MASTER 500 A -DL Delayed Pro- lease /purchase plans ... mono and enjoyment of FM radio listening." grammer. Designed to provide a stereo models . . . rack -mount or 6- second to 16- minute delay in the compact models . . complete line broadcast of program material, the of equipment and accessories . 500 A -DL makes possible "instant 24- hour -a -day ruggedness and de- censoring ". . . lets you delete ob- pendability ... ironclad, full -year jectionable program material from guarantee. BROADCAST ELECTRONICS, INC. 8800 Brookville Road, Silver Spring, Maryland Telephone: Area Code 301 JUniper 8 -4983

Sold nationally by: Canada: ELECTRONICS Northern Electric VISUAL COMPANY LIMITED 356 W. 40th St., New York, N.Y. Branches from coast -to -coast in Canada

Circle Item 5 on Tech Data Card 6 BROADCAST ENGINEERING

www.americanradiohistory.com Now... a new MW]a1 Sound Recording Tape!

Ta e a piece of the new Eastman tape. See how tough it is ... how clear it breaks under stress.

Look! No stretch...when it breaks -it breaks dean!

NEW! Support material for EASTMAN Sound Record- New "R- type" binder.This gives a smoother, tough- ing Tapes is DUROL Base. A specially prepared form of er surface, thereby reducing tape noise and distortion. In cellulose triacetate- smooth, tough, durable, highly addition, it provides extreme abrasion resistance, pre- flexible - provides high strength with low elongation. venting oxide build -up at t -e head. Even more im- When equipment accidents happen, it breaks clean. portant, however, are the amazing magnetic properties Splices are made easily, quickly -with minimum pro- of coatings of "R -type" binder which make possible gram loss. two superlative tapes -both available now .. . Another important feature: "Lifetime Coding," At leading electronic supply houses: Type A303, a your assurance of highest quality. Printed on the back cf vastly superior low -print tape with output comparable to a fine purpose also Type A304, a high - all EASTMAN Sound Recording Tapes is a continuously general- tape .. repeated, permanent legend. This identifies Eastman output tape with remarkably low print -through. Kodak Company as the manufacturer and provides a Easlmmi Kooaa Ccmpany, MCMLXI convenient means of indexing these tapes.

For information, see your electronic supplier or write Magnetic Products Sales

EASTMAN KODAK COMPANY Urique ultra- handyThread -Easy Reel with Rochester 4, N.Y. indexing scale and built -in splicing jig. Circle Item 6 on Tech Data Card December, 1963

www.americanradiohistory.com PLANNING THE FM by George W. Yazell* -Some considerations in the selection of stereo STEREO INSTALLATION equipment for new installations.

before an order is placed for new ter or associated device for sale to FM stereo station equipment (Figs. broadcast stations must obtain FCC 1 and 2). In preparing his recom- type acceptance. In doing so, com- mendation, the engineer will re- plete and authentic test data is sub- view descriptive literature, adver- mitted for the Commission's review tisements, and instruction books. He and approval. Type acceptance by will seek information and advice the FCC is your assurance that the from his consultant, other station equipment will meet certain speci- engineers with stereo experience, fications. and sales representatives of broad- Thus you can either draw straws, cast equipment manufacturers. His or accept the views of the "advisor" thinking may also be influenced by with the most forceful opinion - magazine articles and advertise- and still feel safe that the equip- ments. ment you recommend will work. A It is unfortunate, but true, that more practical solution would be during the engineer's survey he will to prepare a list of equipment and encounter many conflicting opin- features you require, with careful ions and claims. Some "advisors" attention to needs peculiar to your may go so far as to imply that their own station; then select the equip- Fig. 1. Typical transmittcr installation. system of stereo signal generation ment which most nearly matches your requirements. In planning a new installation, is the only one worthy of considera- tion, and all the rest have so many the broadcast station engineer will List What You Have be called upon to evaluate the shortcomings as to be impractical products of various manufacturers or even unworkable. The first step is to list and eval- The simple truth is that any uate any equipment, facilities, and *Gates Radio Co., Quincy, Ill. manufacturer offering a transmit- assets already available for the pro- posed installation -even if it is only a construction permit, a bank ac- count, and a plan of operations. Some items to consider include: 1. Ask management for a budget. This is probably the most sig- nificant factor in your recom- mendation. You should set both a practical budget and an abso- lute top limit. If you find it im- possible to do the job within the budget limitations, do not hesitate to say so. Point out that stereo is a two channel sys- tem and that in addition to spe- cial transmitting equipment, the studio installation will require two of each amplifier, loud- speaker, telephone line, etc. Therefore, a stereo installation will cost considerably more than monophonic facilities. 2. Review the program plans for the station. The quantity, com- Fig. 2. Modern control roam equipped for stereo broadcasting. plexity, and flexibility of the BROADCAST ENGINEERING 8

www.americanradiohistory.com audio equipment selected must STUDIO TRANSMITTER adequately meet these needs, ANTENNA with some reserve facilities for

STEREO future expansion. htICROPNONEi___ STEREO aO STEREO a LIMITING GENERATOR 3. You may presently have an FM, CONSOLE AMPLIFIER ANIMMere FREQUENCY& AM, or TV station -or a com- MODULA TION TURNTABLES SCA MONITOR TOWER bination of these. In this case IBACKGROUND LIMITING SCA MUSICI AMPLIFIER GENERATOR you can probably count on using PROGRAM SOURCE existing studio facilities, some TAPE the RECORDERS of the technical equipment, ACCESSORY tower, remote control facilities, ITEMS I. SPARE PARTS and technical manpower. REMOTE 2. TEST EQUIPMENT AMPLIFIERS 3.5IGNAL LIGHTS ACCESSORY 4. Consider the abilities of your (WIRING SUPPLIES ITEMS 2 5. CLOCKS technical staff. You may be the 6. MUSIC LIBRARY 1. SPARE PARTS FM OTHER 7. NEWS SOURCE 2. TEST EQUIPMENT TRANSMITTER PROGRAM COAX LINE only engineer, or may have &.OFFICE EQUIP 3.WI RING SUPPLIES SOURCES available a large staff of tech- 9. FURNITURE 4. TOOLS nical personnel. In any event, select equipment having circuits Fig. 3. Block diagram of typical stereo station equipment layout. and components your techni- cians can install and maintain. 4. It will be wise to purchase as day's FCC Stereo Specifications from a were only as 5 Survey the supply situation. many items as possible established recently Determine the location and single source to take advantage as 1961, there will be little used stock capabilities of electronic of: compatability of equipment equipment available. In the major- supply houses in your area. that is designed to work to- ity of cases, converting old mono- Keep in mind that any elec- gether as a system, coordinated phonic equipment will be difficult, tronic component must eventu- shipments and service, possible costly, and the end result may be ally fail; and an inexpensive lower cost because of quantity less than satisfactory. Old "dual - component can cost hundreds purchase, and - if required - channel" audio consoles have been of dollars if you are `off the simpler financing arrangements. successfully converted, but in the air" several days while a re- process usually require almost com- Making A Decision placement is being flown in plete rebuilding. It is necessary to from a distant source of sup- After considering the points out- install dual faders, correct phase ply. If the supply picture is lined above, and making the lists, differences, and balance gain be- discouraging, you can best pro- you are ready to select equipment. tween channels. tect yourself by selecting practi- If the budget is limited you may Used FM transmitters are fre- cal equipment employing read- investigate the possibility of some quently advertised, but many are ily available components -and used equipment. However, since to- left over from the early days of FM. ordering an adequate supply of Some transmitter manufacturers of the late '40s are no longer in busi- spares for parts you cannot ob- COMPARISON CHART ness. Replacement tubes and parts tain locally. ITEM 5KW FM are difficult, if not impossible, to List TRANSMITTER get. Some older transmitters lack Your Needs RBAY FM ANTENNA stability and some contribute to Your next step is to prepare STEREO degradation of stereo separation, as complete a list as possible of CONSOLE not the the total equipment requirements. because they do maintain LIMITER relationship between Sketch a block diagram of your proper phase and sidebands. If such proposed layout (Fig. 3). Then pre- upper lower J a transmitter is to be used, it prob- pare a chart of all the equipment Please turn to page 35 you will need with space provided Fig. 4. Simple product comparison chart. for prices, data, and notes on each CASCADE FM EXCITER device (Fig. 4). As you prepare these charts several things will be- CRYSTAL CASCADE FREQUENCY FREQUENCY OUTPUT +10 WATTS OSCILLATOR MODULATOR MULTIPLIERS' EULTIPLIERS AMPLIFIER come evident: BB -IC& MC 1. You will probably discover more equipment is needed than you LR f i a originally anticipated. L 67KC SCA -- 38 KC HA E MAT IX L-R BALANCED GENERATOR (NOTE: AMC USED 2. In determining what must be MODULATOR MO ULATOR R 0- DSB ONLY WITH purchased, you must carefully MONAURAL integrate your needs with equip- f f3&KC BROAD CASTI PILOT ment now on hand. 19KC 42KC SCA DOUBLER CARRIER GENERATOR 3. Your ultimate decision will de- OSCILLATOR pend on many interacting fac- tors rather than on one out- STEREO GENERATOR SCA GENERATORS standing feature of a particular device. Fig. 5. Functional block diagram of a stereo /SCA generator.

December, 1963 9

www.americanradiohistory.com MONITORING AND by D. Ridgely Bolgiano* - Three methods of oscilloscopically monitoring THE MEASURING FM and measuring the FCC -approved STEREO BROADCAST FM stereo signal.

Monitoring of compatible stereo- appear during the first 90° of pilot phonic FM broadcast signals has subcarrier deviation after the sub - not as yet been standardized to any carrier crosses the time axis. particular accepted method or in- One way to monitor these condi- strument. tions might be with meters. Two The FCC has clearly specified meters could be connected to moni- criteria for meeting monophonic tor the sum and difference audio. FM broadcasting standards. There If both meters show identical indi- are already methods of meeting cations during program transmis- these criteria, which are known to sion of right or left signals only, any station operator who completes Fig. 1. Monitoring composite signal with then the first two characteristics a proof of performance. There now internal sweep synchronized on the audio. would be established. A third meter exists the problem of monitoring could measure phase differentials the stereo FM signal. This prob- since sound can be received stereo- between the pilot subcarrier and the lem may be solved by examining phonically if they are established - stereophonic subcarrier sidebands. three composite- signal characteris- even if the third criterion is not. Once calibrated, such meters would tics which the stereo FM operator However, it is desirable that a prop- provide reasonable day-to -day indi- must keep within limits if he is erly phased receiver be capable of cations of operation. However, no to transmit a good and consistent receiving separate channels when such instruments are commercially stereophonic signal. These three tuned to any station transmitting avialable. characteristics can meet FCC stand- FM stereo. For this to be true, it ards when: is necessary that all stations main- Oscillographic Monitoring tain the same phase relationship 1. The ratio of main channel be- The oscilloscope can provide all modulation to subchannel tween their 38 -kc sidebands and the means for stereo measurements modulation for a left -only the 19 -kc pilot (synchronizing) sub - and in a fashion that can be used or right -only signal is close carrier; this meets the third speci- for regular control room monitoring to unity. fication. The FCC has stipulated operations. There are three methods that the stereophonic subcarrier, its that have come to my attention in 2. The same ratio is maintained sidebands, and the pilot subcarrier for moni- for all audio input frequen- the use of the oscilloscope shall cross the time axis simultane- toring the composite stereo signal. cies from 50 to 15,000 cps. ously and in the same direction - Using Audio Waveforms 3. The 38 -kc sidebands are in when a positive -going cycle of - The familiar pattern in Fig. 1 phase with the 19 -kc pilot left signal is applied to the trans- subcarrier. mitter. This determines that alter- may be formed by connecting the discriminator output to The first condition determines nate time -axis crossings of both the composite vertical input; the whether there is adequate cancella- subcarrier and the 38 -kc sidebands the oscilloscope is synchronized tion in matrix -type receivers, or (the stereophonic subcarrier side- horizontal sweep audio to display one or whether residual signal remains in bands) should coincide with each with the If a left or right the "off" channel in time- division other. Also, the FCC specifies that two audio cycles. signal is supplied to the transmitter, receivers. the left channel information will The second simply says that lack of separation may be easily good separation is desirable at all seen. The upward modulation en- audio frequencies and not at just velope should not extend below the one. Thus, a monitoring method time axis and vice- versa. The pilot should show separation at all audio subcarrier may be seen as alternate frequencies. The FCC requires 29.7 tips extending below or above the db separation as a minimum at all time axis, as the case may be. This audio frequencies transmitted. Editor's Note: This paper - which was The first two conditions are basic. presented at the 1963 Audio Engineering Society Annual Meeting - is based on *Bionic Instruments, Inc., Bala- Cynwyd, Fig. 2. Bow -tie monitoring with 19 -kc sine work performed at Drexel Hill Associ- Pa. wave (pilot sub_arrierl on shown X -axis. ates, Inc., Dover, N. J.

JO BROADCAST ENGINEERING

www.americanradiohistory.com method of looking at the composite signal is useful primarily when sine waves are transmitted, since the oscilloscope must maintain synchro- nism with the audio signal - for complex program material, the au- dio frequency is constantly chang- ing. As long as the trace on the oscilloscope screen can be made to "stand still," this waveform is "ab- solute"; it is dependent only upon receiver and oscilloscope amplifier linearity. This method is also Fig. 3. Left signal modulation; employing Fig. S. Main channel, or monophonic use- pilot -synchronized method of monitoring. modulation; pilot- synchronized monitoring. ful for determining whether lack of a unity ratio (characteristic 1) is first method, but with one slight in the odd- numbered quadrants of caused by phase delay or by ampli- difference. This time the sweep the pilot subcarrier. The right signal tude differences between the sub - should be synchronized with the appears during the even -numbered channel and main channel modula- pilot subcarrier and, for easy view- quadrants of the pilot subcarrier, tion; this is the only method that ing, may best be adjusted so that as may be seen in Fig. 4. shows the actual audio waveform. about two cycles of the pilot sub- This pattern also shows immedi- carrier can be seen on the screen. ately whether there is a unity ratio Bow -Tie Method 1 have found this pilot-synchro- between the main channel and sub - A second method (the bow -tie) nized method of monitoring to be channel modulations. Separation ca- gets its name from the pattern pro- excellent. The only variables in- pability may be measured as the duced (Fig. 2). This system of mon- volved are the linearity of the re- amplitude ratio between the modu- itoring can be used during pro- ceiver and the linearity of the os- lated channel and the unmodulated gram transmission. The pattern is cilloscope vertical amplifier. With channel. obtained by connecting the compos- this method you will see patterns If the right and left signals - in ite signal to the x -axis amplifier such as those shown in Figs. 3 phase with each other and of the and the 19 -kc pilot (in its unmodu- through 8, which show immediately same amplitude (R =L) - are ap- lated form) to the y-axis amplifier. which channel is left and which is plied to the stereophonic transmit- The pattern is, however, subject to right. ter, the pattern shown in Fig. 5 is phase shift. The 19 -kc and the com- In Fig. 3 notice that the audio produced. This is the same as that posite may not arrive at the oscillo- signal appears to modulate the pilot produced by a monophonic (L R) scope deflection plates in phase with subcarrier principally after the sub- transmission with the pilot subcar- each other. One should not use this carrier crosses the time axis and rier on. method for monitoring the phase of before it reaches its peak (either If right and left signals of exactly a stereo transmitter unless the phase upward or downward). This agrees opposite polarity, but the same am- is known to be correct initially. with the FCC specification for a plitude (R =L), are applied to the A very clear distinction between left signal. The upward swing is stereophonic transmitter, the pat- the left and right channels can be created by the positive left signal tern shown in Fig. 6 is produced. obtained if the pilot carrier is and the downward swing by the Notice now that the pilot subcarrier doubled to 38 kc before applica- negative left signal. Notice that, if can be seen only at its peaks and tion to the y -axis input. With you reverse the x -axis input leads, time -axis crossings, and that identi- proper phasing, the pattern on the the signals remain in the same cal modulation is readily apparent oscilloscope screen will form a tri- quadrants of the pilot subcarrier - in each of the pilot subcarrier quad- angle pointing leftward for left sig- thus still indicating a left signal. rants. Alternate nulls in the signal nals and rightward for right signals. Making the same swap with either appear in a straight line along the Just reversing the x -axis oscilloscope of the other oscilloscope monitor- time axis. This shows that the pilot leads will reverse left and right on ing methods would reverse left and subcarrier is in phase with the the pattern. right. Thus, the left signal appears Please turn to page 28 Pilot -Sync Technique The third method of oscilloscopi- cally monitoring the FM stereo- phonic signal does not depend up- on any external signal phasing. It will show clearly and immediately whether the conditions (unity am- plitude ratio at all frequencies and phasing between the stereophonic subcarrier and the pilot subcarrier) are met. The composite signal is connected to the y -axis and the os- Fig. 4. Right signal modulation; using Fig. 6. Subchannel only, or reversed cilloscope sweep is used as in the pilot- synchronized method of monitoring. polarity modulation; pilotsync method.

December. 1963 I I

www.americanradiohistory.com by Ed Murdoch* - Part Four. Continuing WHEN THE PROOF -OF- the discussion of troubleshooting techniques; this month, distortion and PERFORMANCE FAILS balance in push -pull stages.

Part Three of this series dis- by tube mismatch. The console out- limiter should be treated in the cussed techniques for tracing noise put stage should be checked first, same manner. It is advisable to sources in the power supply, and before the limiter or line amplifiers. check balance in all push -pull on through the audio modulation The static (no signal) balance can stages, although the output stages portions of the transmitter. Pro- be checked by measuring DC volt- will still be the most likely source cedures for balancing the modulator age between the push -pull tube of mismatch distortion. The bias tubes were also described. This plates with a VOM (do not use a tube of the limiter should be out month, the discussion will continue VTVM). If the tubes are in perfect of the circuit, as during the full with relationships of distortion to static balance there will be no volt- proof. balance in push -pull stages, and age indication. However, this is It might be thought that an other amplifier considerations. seldom the case. Generally, there easier alternative would be to bal- After balancing the transmitter will be some indication of voltage, ance the stage by measuring fre- modulator tubes, it may be found ranging from a mere "flicker" to quency response with different pairs that total distortion still exceeds (or several volts. All spare tubes of of tubes and choosing the best pair; approaches) the limits - even that type should be substituted until minimum distortion would thus be though the transmitter is within a pair is found that produces mini- attained automatically without all bounds when measured separately. mum DC voltage between the the trouble of distortion measure- It is then time to check the balance plates. ments. This system, however, would of the other push -pull tubes in the Console Output Amplifier result in only an approximation of audio chain. (NOTE: For purpose is possible Before beginning the balancing minimum distortion. It of discussion continuity, the bal- of tubes to be very procedure, the console should be for two pairs ancing of the transmitter audio yet one given a separate distortion and re- close in frequency response, drivers was not treated in its proper pair might produce less distortion. sponse check for reference (Fig. 1). place. Actually, the audio drivers according to Then as the tube pairs are alter- If the tubes are paired should be checked before balancing measurement, the re- nated, a spot -check of distortion distortion the modulators and in accord- will take care of - and a comparison of response sponse generally ance with the following discussion. as previously stated, should be made at 25% and 100% itself. However, be verified via Tube Balance of normal output level (generally the response should VU meter as the tubes measured on the output VU meter). the output In any amplifier consisting of are alternated for minimum distor- several push -pull stages, the high - The pair which shows up second best on the minimum DC voltage tion checks. level or output stages will be the When making the spot distortion test should also be given a spot - major sources of distortion caused careful to maintain check. checks, be very the same amplifier output level WMMB, Melbourne, Amplifier stages which have a *Chief Engineer, 100 %, whichever the case Fla. single balancing resistor shared by (25% or for all three spot fre- two push -pull tubes should be may be) "zeroed in" with a VOM, while the quencies. I o I 0151..A ANAL. HOIST. ANAI amplifier is inoperative, before at- Component Failure -DC Checks tempting to balance the tubes by So far, the discussion has con- .f`. (TI ITI intrinsic match. That is, the balanc- cerned only distortion caused by OSC CONSOLE LIMITER ing control should be adjusted so it tube unbalance, and mainly with presents equal resistance to both respect to achieving a series of tubes. Then, after the best "natu- minor improvements in stages which Q rally- matched" tubes are found, a may already be operating within /7\ r slight readjustment may be made Osc DIST. ANAL. tolerance when considered sepa- to achieve zero voltage between the rately. But what if the console or plates but the results should be xMTR - limiter should show rather high C'MiT.- LIMITER verified by distortion measurement. distortion and after you become ORAN M TTER IS SPOT -CHECKED - íEP>R *TFL Other Amplifiers groggy swapping tubes around, it apparent that even the Fig. 1. Spot checks for isolating trouble. Next, the line amplifiers and becomes

I2 BROADCAST E N G I N E E R I N G

www.americanradiohistory.com best balance makes no appreciable ancy between the bias voltages at or perhaps a leaky screen-grid by- dent in the distortion? Here's the grids of push -pull tubes, it is pass capacitor connected to another where the fun begins. You might possible that a coupling transformer tap along the same winding. With even sell tickets to the perform- is faulty (Fig. 2A) and a portion of the equipment turned off, measure ance, because you are now in for the preceding plate voltage is being the DC resistance from the sus- a gay, carefree spree of trouble- applied to one of the grids (the pected tap to the core. To avoid shooting, and surely will want the grounded center tap of the sec- confusion, this should be measured neighbors there when you start ondary would prevent it from ap- first with all primary taps con- running around the control room pearing at both grids). This can be nected and then with all primary yelling for a psychiatrist. verified by disconnecting the trans- taps disconnected - especially if former indicate Circuit Voltages leads from the grids, leav- the first reading seems to ing the center tap grounded. Touch a short to the core. In the latter While distortion due to tube un- the positive lead of a VOM to the case, an ohmmeter should show in- balance generally occurs in the out- secondary leads to measure any finite resistance from the primary put stage, that caused by a faulty DC leakage from the transformer tap to the core. When a short exists, component can occur anywhere in primary. This test can also be ap- the resistance will range from a few the sequence. As a preliminary step, plied to single -ended stages if the to several thousand ohms. it is advisable to measure all DC bias deviates from the proper value. Transformer windings do not plate, screen, and cathode voltages, A similar, but more common, always short to the core. Some- and compare them to the voltage situation can occur in resistance- times one side of a primary wind- charts in the amplifier maintenance coupled amplifier when the ing of a push -pull unit will break manual. stages coupling capacitors become leaky down to the other side, or one part If any obvious discrepancies are (Fig. 2B). A portion of the preced- of a winding may short to another found, it should be relatively easy ing stage's plate voltage is applied layer of the same winding (Fig. to locate the faulty component. But, to the grid, thereby decreasing the 2C). Either of these conditions will before you start hauling out any normal negative bias voltage. This result in very little or no change in suspected resistors or capacitors, condition can be checked in a simi- DC voltage at either tube. The con- inspect all wiring in the associated lar manner - disconnect the grid dition cannot be corroborated by circuit. Go over it very carefully to end of the capacitor and measure pulling tubes out and checking see if there are any minute solder with a VOM for the presence of plate voltage - there is no short to droplets, or wire ends poking leakage voltage. If any leakage is ground to draw current through the through insulation, causing a partial discovered, the capacitor should be winding resistance when the tubes or dead short to chassis, tube replaced. Similar leakage through are out. If this condition is sus- socket terminals, or other wires. defective feedback capacitors can pected, the quickest check is to And if the amplifier is an old one also cause an erroneous bias on measure the resistance of each half which has had a good deal of the grid. of the winding. Any serious dis- sporadic maintenance, go over the crepancy indicates a shorted wind- circuit carefully to see if any wires Plate Voltage ing. With a single -ended stage, in have been disconnected and then DC unbalance can also be caused which this comparison is not pos- fastened to the wrong point. by faults in a transformer primary sible, the instruction manual should winding. A winding shorted to the be consulted for the normal Bias DC core will bypass part of the plate primary resistance. If not, the tube- Measure the voltage between voltage for that side of the stage socket resistance chart will be a grid and cathode to ascertain that (if it is push -pull). This can be possible aid. However, these helps the required bias voltage is actually checked by removing the tube and will not definitely put a conclusive appearing at the tube grid. By measuring to see if low voltage still finger on a defective primary. Un- making these DC measurements it prevails at the tube socket. How- less the normal primary resistance should prove fairly easy to locate ever, before snatching out the trans- is given in the manual, the quickest an open (or changed) resistor, an former in a paroxysm of glee, way of pinpointing a shorted pri- open transformer winding, or simi- make very sure there is no other mary in the transformer of a single - lar fault. cause for the condition - such as ended stage is by comparing its If there is a noticeable discrep- the aforementioned solder globule resistance with that of a replace-

CAPACITOR LEAK

f- "J'Jl -'i WINDING SHORT - ^llf. SHORTED,- l PRIMARY r TURNS

DC *DC

+DC n

(A) Shorted turns between windings. (B) Coupling capacitor leakage. (C) Turns shorted in the primary.

Fig. 2. Some causes of DC unbalance in push -pull amplifier stages.

December, 1963 13

www.americanradiohistory.com iPREAMP

RELATIVELY BADLY CURVED STRAIGHT STAGE IS PRE -AMP OK DISTORTING

Fig. 3. Checking for audio frequency symmetry. Fig. 4. Cheek for distortion in low -level stage.

ment unit. In most broadcast equip- comparing the relative signal levels. nal sweep generator of the scope ment, the only single -ended stages Continue this process at the grids; is not used; the "Horizontal" switch are in low -level sections (i.e., pre- and so on back through the preced- is changed to "Horizontal Input" amplifier units); hence there will ing push -pull stages. If a point is and the signal is furnished by the generally be one or more similar reached where there is a noticeable audio oscillator. To avoid inherent transformers available for compari- difference in AC signal between the distortion of the waveform, espe- son. Sometimes, substitution of a two sides, the defective component cially when checking at a grid, a new unit is the only practical solu- (or condition) should be in that low- capacitance probe should be tion. section. employed (such a probe is not rec- If no discrepancy is found in the ommended for noise hunting be- Dynamic Checks push -pull stages when tested in this cause it has a rather high attentua- (Editor's Note - Watch for an manner, the feedback loops should tion factor). If the low level stages article soon showing a dynamic be reconnected; and the previous are distortion free, the resultant method of testing transformer wind- measurements repeated for all scope trace should be a straight ings for single- or few -turn shorts.) stages. If an error in symmetry line canted at 45° (as shown in These DC measurements will should now be found, one of the Fig. 4, denoting an in -phase con- usually turn up the faulty com- feedback ladders must contain a dition). If nonlinearity is present ponent; but occasionally everything faulty component. In this event, the (resulting in distortion) this straight seems just jim -dandy from a DC same comparison tests applied to trace will "bend" - the amount viewpoint, yet distortion is there corresponding points along both depending on the degree of non - anyway. The trouble could be due ladders will assist in locating the linearity. The source of the non - to a faulty coupling or bypass ca- feedback trouble. linearity may be isolated by prob- pacitor, or perhaps it is one of those Normally, objectionable distor- ing at various points. Other than contankerous cases in which a com- tion will occur only in the higher capacitors and resistors operating ponent deviates only under actual level stages. However, if the meas- erratically under signal conditions, dynamic operation. So, if DC urements taken so far indicate the input transformer may be de- checks do not indicate the trouble, nothing amiss in the last stages of fective. the next step is to feed a signal the amplifier, the next obvious step Because of a certain amount of from an oscillator into the ampli- (other than hara -kiri) is to see if nonlinearity within the oscilloscope, fier, and make AC measurements. the waveform is distorted some- a comparison of conditions should Although an oscilloscope may event- where before it reaches the push - be made in another preamp stage ually be required, it is best to start pull sections. Although the distor- before reaching a final decision with a VOM or VTVM adjusted tion analyzer may be "gimmicked" concerning the stage in question. for "output" measurements (a DC into low -level circuits (for special NOTE: The 45° cant of the trace, blocking capacitor may have to be application which may at times be mentioned above, is not automatic. added if the meter does not have advantageous in such difficulty as This angle is chosen because it is one). Adjust the oscillator for a we are now considering), the pro- convenient for observation; the medium audio frequency (400 to cedure requires a special knowledge scope amplitude controls must be 1000 cps) and check the amplitude of many factors and isn't of practi- adjusted to produce an approxi- symmetry (Fig. 3) of corresponding cal value to the `occasional' trouble- mate 45° (in phase) trace. Also, the points in all the push -pull stages, shooter. production of a "closed" line as- beginning with the output stage. It is at this point that the oscillo- sumes that the amplifier signal at First, disconnect feedback networks scope may again be brought into the test point is exactly 90° out of at the point where they connect play, although in not quite the phase with the scope's horizontal into the first stage in the loop; re- same fashion as before. Since it input - which is not always the adjust the preamp attenuator for is difficult to ascertain distortion case. Depending on circuit condi- normal output level of the output levels lower than 5% in the oscillo- tions at the point of measurement, stage. With the negative (common) scope reproduction of a waveform, the line may tend to open into an meter lead grounded, use the posi- the scope will be used to display ellipse; if so, it should be a sym- tive lead to measure signal voltage amplitude linearity at the various metrical ellipse if the stage is not at the plates of the output tubes, points of measurement. The inter- distorting.

14 BROADCAST ENGINEERING

www.americanradiohistory.com What compact can do everything a console recorder can? AMPEX PR -10

The Ampex PR -10 gives you all the features, all the electro- dynamic clutch system to give you fast, gertle performance of a console recorder. Even remote control. starts and lower brakirg tension. if you want to monitor And A's all wrapped up in a suitcase -sized package. on- the -spot, the PR -10 has A -B switches, VU meters, That means you can take a complete re- phone jacks,output circuits. Moreover,electri - cording studio out into the field, into the cal alignment controls are accessible through school, the church, industry- anywhere you the front panel. You get all this plus a new need it. The PR -10 'eatures positive push- Ampex "FourStar "one year warranty. Fordata button controls; record -safe switch; and sep- write the only company with recorders, tape & arate erase, record and playback heads. And memory devices for every application: Ampex r-1 ('s'I : there's room for an optional 4 -track stereo or j. Corp., 934 Charter St., Redwood i F additional playback head. There's also a new City, Calif. Worldwide sales, service l'."IPEX Circle Item 7 ea Tech Data Card December. 1963 I5

www.americanradiohistory.com ANTENNAS FOR Technical Talks* - Requirements for stereo transmitting antennas with FM STEREO methods for achieving desired results.

This month we are going to talk a beach or a roaring that comes the equipment used by your lis- about antenna systems for stereo and goes. It is caused by a trouble- teners. So the best approach for the FM. In general, this is not an espe- some acquaintance of ours, phase station engineer is to ensure that cially deep subject. The require- shift. As the FM signal travels from he puts out the best possible stereo ments for best operation of any FM the transmitter to the receiving an- signal. If he knows his transmission station call for broadband antennas tenna, there is generally a slight is clean, he at least has right on and adequate power capability. change in phase. In the case of his side! Stereo FM calls for an antenna with monophonic transmission this is not Crosstalk the ability to transmit the subcarrier important; the ear cannot detect Once the FM signal has left the sideband pairs as well as the FM phase shift in a single channel. But antenna, there is not much that can fundamental without frequency dis- as soon as stereo is added, the be done to keep it pure. But, until crimination or phase distortion. changes by multipath re- produced it actually leaves the antenna, you flections or variations in the rela- must take good care of it. This Other Side of the Coin amplitude and phase of the tive means you should avoid crosstalk Perhaps a quick look at require- sideband pairs cause a change in and poor VSWR in the antenna ments from the receiving end might the reinsertion oscillator, with a system. This is merely an extension be helpful. The average FM set subsequent variation in separation of good engineering practice, but it that uses the power line for an an- between the left and right channels. is decidedly more important in tenna does not seem to have the This shifting causes the "seashore" stereo. Therefore, Iet's run over same sensitivity as an AM receiver. roar. A properly oriented receiving very briefly the principles of the For ordinary monophonic FM will gen- these antenna of good design FCC-approved stereo FM system. antennas and receivers are pretty take care of such propaga- erally The Commission did not say that good, and often provide better re- tion problems, although there are any particular maker's system has sponse than a similarly priced AM locations where it seems impossible to be followed, any more than they receiver; and, they are relatively good stereo from certain sta- to get did in the case of color television. free from noise. But as soon as tions. The situation is similar to In that case, the NTSC system was stereo is added to the signal, the that of television where a particu- specified; the method of achieving addition of a stereo FM adapter to bad multipath situation pro- larly it was left to the imagination of the receiver often reveals a poor duced ghosts so bad that reception the various manufacturers. So it is state of affairs in signal reception. In TV, the eye per- was ruined. with stereo FM. Maybe the sound is good on reflections; in stereo, the ceives the In the FCC -approved system, the nearby stations. But so often there hears the results. ear main FM carrier is modulated by is a peculiar sound like waves on - Transmitter Responsibilities the sum of the left- and right - Unfortunately, you at the trans- channel information; so a listener *by John H. Battison, Consulting Editor, Washington, D. C. mitter end cannot do much about Please turn to page 27

ANTENNA CAVITY

BALUN

VIDEO XMTR SIGNAL AUDIO XMTR SIGNAL CAVITY

Fig. 1. Diagram of common bridge dip :exer. Fig. 2. Basic schematic of notch diplexer. BROADCAST ENGINEERING 16

www.americanradiohistory.com KEEP STATION PERFORMANCE UP... MAINTENANCE COSTS DOWN with Telechrome' Transistorized Video Broadcast and Test Equipment

SET UP lb 0 0, 410 MU_TleUnsT I .., 0 ., ..n, w t `' ,. 9

tvt 5 SIT 57 et S ON [C3 wi S,/.Itl,t

S"MeSiEP ilMiliCT5ti iv wbtae -WIWI it, TOT t: lr SCA 4 ,Spt(41 a i fP

Model 3508A1 Video Transmission Test Setnowwith 1/2 T pulse* ¡ISr.InJ n.lnn

FEATURES: Rack mount or portable. Carrying case contains 13a" utility drawer which can be removed for installation of an EIA Sync Genera- tor (Model 3507A1), is pre -wired for sync generator. All controls conveniently located on front panel. Operates from self contained non -interlaced sync, plug -in EIA Sync Generator, or external EIA Sync and Blanking. VIT Operation -when used with external VIT Keyer, provides vertical interval test signals through a high impedance (line bridging) output. L J Low distortion multiburst- plug -in oscillators permit optional selection of frequencies to 12 MC.

Preset 3, 5 and 10 -step stairsteps with variable APL modes. C O M P A N Y s enthCo and 3.58 MC sub -carrier on all AMITYVILLE, NEW YORK: 185 DIXON AVENUE, (516) 541-3600 * 2T, T and 1/2T(.250,.125 and.062 µsec) Sine squared SANTA ANA, CALIF: 2509 SOUTH BROADWAY, (714) 546.2881 pulses. Window signal also sine -square filtered.

NOW - condensed into one small lightweight portable unit -fully transistorized. Multiburst Stairstep Sine Squared Pulse & Window Optional EIA Sync Generator Multiburst Signal -Line Rate -Internal Sync 10 -Step Signal -Line Rate- Internal Sync Sint & Window Signal -Line Rate -Internal Sync

Circle Item 40 on Tech Data Card December. 1963 17

www.americanradiohistory.com PHASE CHECKING OF by Harry A. Etkin* - Practical means for determining the relative phase of STEREO CHANNELS channels in a stereo system.

meter to indicate the combined STEREO PICKUP outputs. Play a good lateral fre- MICROPHONES

quency record and observe the VU LOUD meter reading for each channel, SPEAKER separately. The readings, if the AMPLIFIER

LITERAL FREQUENCY vu HST channels are properly balanced, FROM AUDIO RECORD RIGHT PRODS should be equal. If the phase re- OSCILLATOR lationship is incorrect, the VU Fig. 1. Checking phase with a VU meter. meter will indicate a reduced read- ing when the channels are con- In FM broadcasting, it is Fig. 3. Setup for checking microphone stereo nected together. Fig. 1 shows the phase with an audio oscillator and scope. of utmost importance that proper equipment arrangement. phase relationship be maintained in plifier channels. Fig. 3 indicates the audio channels to produce Another System -Scope the system used for testing micro- pleasant music with tonal balance, The second method for making phones. and sound perspective with depth the phase check of the stereo audio An effective method of testing and "spaciousness." When audio chain is detailed in Fig. 2. The es- speaker phase is shown in Fig. 4. signals are out of phase, music sential equipment to perform this Both microphones are placed in reproduction suffers from cancella- test are an audio oscillator and an front of the left speaker, and a 200 tion and loss in the low frequency oscilloscope. The oscillator is con- cps tone is fed to it. The right ranges, and undesirable high fre- nected to the scope; the audio sig- microphone is then placed in front quency products. Consequently, the nal connected to the vertical and of the right speaker and the same broadcaster must realize the impor- horizontal inputs of the scope. signal fed to both speakers. An tance of checking and maintaining When you feed a 400 -cps sine wave identical figure should appear on proper phase between the two to both inputs of the scope, a the oscilloscope. channels. Either of two test meth- straight line - sloping upward to ods may be employed. the right - will appear. Its angle Conclusion on the screen should be adjusted One Way -VU Meter The test methods and techniques to 45° by manipulating the scope's in this The first method for phase check- described and illustrated gain controls. This step calibrates article will contribute to high quality ing is to patch together the outputs the scope for subsequent phase reproduction of both music and of the left and right channels either checks. This linear waveform cor- material for both at the pre -amplifier or line ampli- voice program responds to an in -phase condition. monophonic and stereophonic trans- fier stage, and connect a single VU Signals of equal amplitude and mission and reception. the same frequency, but 180° out *Staff Engineer, WQAL -FM, Philadel- of phase with each other, would phia, Penn. result in a straight line sloping 45° MICROPHONES AMPLIFIERS AMPLIFIERS upward towards the left. A perfect LEFT

AMPLIFIERS circle appearing on the screen would IN AUDIO CHAIN OSCILLOSCOPE indicate a 90° phase difference.

Making the Test FROM AUDIO OSCILLATOR After setting up the audio oscil- lator and oscilloscope as described, the broadcaster can readily de- termine the phase relationships RIGHT between stereo amplifier chan- nels, microphone setups, and loud- speakers. Fig. 2 shows the equip- Fig. 2. Setup for checking amplifier phase Fig. 4. Setup for checking speaker phase with audio oscillator and oscilloscope. ment setup for checking stereo am- with audio oscillator and oscilloscope.

18 BROADCAST ENGINEERING

www.americanradiohistory.com SARKES TARZIAN Tube Replacement Silicon Rectifiers

BIG in broadcasting... More and more broadcasting stations of all kinds are proving that the reliability and long, long life * of these units pay off in station on -time. Send for free re- placement chart covering 95% of the vacuum tube rectifiers now in common use, price information, and case history data. * Not to mention instant warm -up, no appreciable heat radiation, no filament supply, compact size, ruggedness, and dc current ratings up to three times as high as the tubes they replace. SARKES TARZIAN Inc. World's Leading Manufacturers of TV and FM Tuners Closed Circuit TV Systems Broadcast Equipment Air Trimmers FM Radios Magnetic Recording Tape Semiconductor Devices SEMICONDUCTOR DIVISION BLOOMINGTON, INDIANA Canadian licensee: Marsland Engineering Limited 350 Weber Street North. Waterloo. Ontario

Circle Item 8 on Tech bolo Cord Dcccmbcr, 1963 19

www.americanradiohistory.com by Harold W. Kassens -A brief FM STEREO -PAST, history, summary of current conditions,

and a look into the future of stereophonic PRESENT, AND FUTURE broadcasting.

Fortunately for all of us, the FM tested at Uniontown, Pennsylvania. little as one hour a day, and others band was, in the beginning, over - using the transmission facilities of as much as twenty -four hours. allocated. If each FM station were Station KDKA -FM in Pittsburgh. What do we learn from these sta- permitted a maximum deviation of After a careful evaluation of the tions? In general, there is content- only 25 kilocycles (plus and minus) findings of the Stereo Committee, ment with the system. It has proven for its aural signal, as a television the Commission, in April 1961, its ability by providing a wonderful station is, the multiplexed stereo announced its decision selecting a new world of public entertainment. and subsidiary services by FM sta- system - proposed by both the In addition to acceptance by the tions would not have been possible. General Electric Company and the broadcasting industry, the general The first important experiments Zenith Radio Corporation - as a public is also accepting stereophonic in FM multiplexing began in 1948. basis for national standards for FM radio. The Electronic Industries As- In 1955 the Commission adopted stereophonic radio. This system was sociation indicates that in 1962, al- rules to permit FM stations to en- determined to be capable of pro- most one -half of all radio -television gage in subsidiary services - such viding, among other characteristics, and radio -phonograph combinations as storecasting and background mu- essentially a flat frequency response produced were capable of receiving sic - as an adjunct to main chan- from 50 to 15,000 cps in each FM stereo. nel programming. Subsequently, in channel and providing a separation This stereo world, however, is 1958 proceedings were instituted by of 30 db between channels over this not entirely one of milk and honey. the Commission to determine other entire audio range. The system is complicated and criti- possible uses of FM multiplex. The first stations to begin stereo- cal, and engineers that are quite At this stage, the Electronic In- phonic programming, on June 1, able are required to keep the equip- dustries Association organized the 1961, under the new rules were, ment operating properly. During National Stereophonic Radio Com- quite appropriately, the General these intervening 30 months since mittee consisting of six panels mem- Electric Station WGHM in Sche- June 1, 1961 there has been an in- bered by outstanding technical per- nectady, New York, and the Zenith creasing demand for suitable moni- sonnel in the industry. This group Station WEFM in Chicago, Illinois. toring equipment to permit the op- was devoted to the purpose of de- Since that time there has been a erator to measure performance of veloping, and recommending to the steady increase in the number of the technical equipment. Several Commission, a set of standards for stations transmitting FM stereo, and papers have been offered that dem- stereophonic radio broadcasting. As today 218 stations have entered this onstrate this need and the steps the a result of the Committee's studies, exciting field of endeavor. The industry is taking to satisfy it. The six systems were rigorously field amount of time devoted to stereo Commission must now establish programming varies from station to standards for type- approval of the 'Broadcast Bureau. FCC. Washington. D.C. station. with some transmitting as monitoring equipment. While progress has continued ill the United States, other countries have also been busy in the FM

---- L L stereo field. Canada has adopted MATRIX P. the United States standards for use

AMP. EXCITER L - R in that country, and several stereo MODULATOR SI DEBANDS stations are operating. Japan is ex- 19KC pected to follow within PILOT GEN. the near TRANSMITTER future. The International Radio A i A B C Consultative Committee, a sub- Z ' T 1 -2` A rt=11 division of the United Nations, has L R DEMATRIX been studying the question of FM AMP. MIXER c--- stereo broadcasting with a view - I.F. AMP L - R Ì DEMODULATOR F.M. DET. SIDEBANDS toward establishing international

OSC. 19KC REGENERATOR Editor's Note: This article is from a RECEIVER paper delivered by the author at the Fifteenth Annual Convention of the Basic block diagram of FM stereo transmitting and receiving systems. Audio Engineering Society.

I E E R I G 20 BROADCAST E N G N N

www.americanradiohistory.com standards. At preliminary meetings 1J9" in Germany last summer, the United MEN IMP States delegation and the European r Broadcasting Union succeeded in obtaining an interim agreement for this international standardization using the U. S. standards. However, at the Plenary Assembly in Geneva, Switz- space erland, last winter we were unsuc- cessful in finalizing the standardiza- reserved tion of this system. It was apparent, however, that several countries in _J Western Europe were satisfied with the capabilities of the Pilot Tone system - as it is known in Europe - and intend to institute stereo- phonic broadcasting before the ques- tion again arises, probably at the next meetings in Vienna in 1965. What does the future hold for stereo? It appears quite obvious as most new FM stations begin opera- CONCERTONE tion, they will do so in stereo. A for the new 607 big difficulty for existing stations - The new Concertone 607 is dimensionally constructed to make it an exact in addition to the extensive technical replacement for the equipment you've been thinking of updating. But it's rearrangement - is the need for a the same in size only. This surpassing tape recorder defies comparison, costly conversion from a monaural really. Its features are fabulous and only a demonstration will prove to to a stereo transcription library. you that its low price is not really a misprint. This is the high -impedance While a brief view over the horizon model of the famous Concertone 605 with provision for plug -in impedance indicates additional stations being matching transformers; precision plug -in head assembly, including four provided, it does not appear that precision heads; separate mike and line controls; professional connectors; any major changes in transmitting calibrated VU meters; delay memory control circuit; automatic glass tape or receiving equipment will occur. lifters (including electric cue feature): sound -on -sound and add sound; The view does foretell, however. solenoid operated brakes; three motors; automatic rewind. See your that demand for high quality com- Concertone dealer, before you decide to replace or expand. ponents will increase as the public becomes more aware of what is SERIES 90 PROFESSIONAL TAPE RECORDERS available in stereo programming. One new development which has occurred is three -channel stereo. Here, the normal two -channel FM ID multiplex signal is supplemented by a low- quality third channel pro- vided by an AM broadcast station. - The question which arises is whether .:iIslip the minimal benefits obtained jus- d. i i :' tify the added spectrum space. most new is Distinguished performer for the Another development "off critical professional. Exclusive Concertone features such the air" relay of stereophonic pro- as "Edit -O- Matic" for high -speed tape cueing and editing. Four heads: 3 -motor gramming. The desire and the need drive, including hysteresis synchronous capstan drive. Maximum in wide stereo - mono versatility and automatic- remote capabilities. for monophonic FM networks has been well established in the past. CONCERTONE 400 COSMOPOLITAN That desire and need now extend themselves to stereophonic FM net- For people on the go... it's the Cosmopolitan ...combination tape recorder and AM radio. A works, but it is considerably more versatile companion and co- worker for business difficult to receive and re- transmit and pleasure travels. Push -button operation.1` Accommodates 5" reels, 2 a stereo signal than a monophonic speeds. This all -transistorized radio -tape recorder brings one. Examination of the basic trans- you big recorder features in mitting and receiving equipment precision -made miniature form. will indicate that there are several possible solutions to the problem. for further But it will require considerable information AMERICAN CONCERTONE, INC. A DIVISION OF ASTRO- SCIENCE CORP. mental exertion on the part of write: Ú149 W. JEFFERSON BLVD. CULVER CITY CALIF. many engineers to arrive at the best Export .I. I). Marshall International, 170 W. Washington, Chicago, Illinois solution. Circle Item 9 on Tech Data Card December, 1963 21

www.americanradiohistory.com to resulting high heater voltage. Re- ENGINEERS' EXCHANGE ducing this voltage by moving the tap on the power transformer pri- mary resulted in a marked improve- ilAl ).:(! ment in reducing noise. On equipment which does not have adjusting taps, installing a line dropping resistor, either in the pri- mary or in the heater string, gave the same results. The size and value of this resistor can be determined by simple Ohms -Law calculations.

5.'

I

NIAC Receiver As alarm relay K 1 is activated, the speaker is connected to the au- by Lawrence I. Presier WERT. Van Wert. Ohio. dio output transformer, replacing the 4.7 -ohm standby load. At the In converting our present CON - same time another set of contacts Jack Field Labels ELRAD receiver - a Karr "Con - by Dale Taylor, Chief Engineer. activates the alarm light (6.3V - No. elert" to receive and display the KZTV, Corpus Christi. Texas - 47) by connecting the 10 -ohm limit- MAC signal, the accompanying We have found that the em- ing resistor and pilot bulb combina- little circuit was developed. It can be bossed -M5, or tion to the filament supply. If addi- tape labels (Dymo built from "scratch" or adapted to into tional control circuits are desired, equivalent) fit perfectly our existing receivers. video and audio jack strips, mak- 6.3V AC relays can be connected a very neat and readable The 600 -ohm line transformer is across the supply end of the alarm ing jack the connected to the NIAC line coming light system. However, the circuit field. They are easily changed if adhesive backing is left covered. into the control board. As a tone should be arranged so the coil cur- signal is received, V1 amplifies the rent does not flow through the 10- Colors can be used for a complete signal to a sufficient level before it coding system. Eight characters will ohm 1 -watt resistor. is applied to V3, the relay rectifier fit each double plug. control tube. A 500K potentiometer Operating Instructions is connected across the input trans- To operate the units, turn the vol- former secondary to adjust the sig- ume control to 8 or 9 (almost full nal to the proper operating level. rotation). When the unit has had The positive voltage developed ample time to warm up, depress the through the 6AL5 is applied to the line check button to hear the input control grid of relay control tube (normal operation is indicated by V4 causing plate current to flow. a few weak "signals" in the back- This, in turn, pulls in alarm relay ground). The unit does not have to K1. be reset (as was the case with most The relay control tube sensitiv- conelrad receivers) when it is first turned on. When an alarm is re- ity can be adjusted by the 25K 5- Preset Recording Clock ceived, listen, take note of what is watt wire -wound rheostat. The 2- by Vernon E. Snider,Technical Supervisor going on, and after the alert, de- mfd 150 -volt electrolytic capacitor Radio Station KXXX. Colby,Kansas. press the check button to return to across the sensitivity control gives Many radio stations have an an- normal condition. Normal volume the circuit excellent hold -in char- nouncer running his own board, level is about half rotation. acteristics. The screen resistor (1K maintaining the program log as well 2 watts) can be made from a 5K as the transmitter log, and along 5 -watt wire -wound pot to provide High Line Voltage with other duties, he is expected to an additional sensitivity adjust- by Peter H. Van Milligan, Maintenance turn on a tape machine to record Supervisor, WMBI, Chicago, III. ment. These two sensitivity controls a network program for delayed should be adjusted simultaneously Over a period of years, the line broadcast. One way to eliminate to achieve the best relay action. voltage throughout the country has part of his problems is to install a The audio voltage is split at the been on the increase. Equipment clock to automatically turn on the output of V1, being used to both designed for 115 volts now may recorder at the proper time. control alarm relay K1 and drive have as much as 125 volts applied. Most clocks listed in radio cata- the control room speaker. The au- We have noticed that trouble in logs are synchronous, constant speed dio circuit uses a 6T8 (V3) driving equipment which has developed units. A source of more accurate a 6AQ5 (V5). shorted or noisy tubes was traced clocks is a school systems supplier

22 BROADCAST ENGINEERING

www.americanradiohistory.com Model TCA7 r-- Color Camera Amplifier , $316 ea. ( r ..,r.. F.D.B. Nashville 4 , ,.:r

Model TPS7 Power Supply $50 ea. F.D.B. Nashville

INTERNATIONAL NUCLEAR CORP. Model TR7 POWER SUPPLY Dropping Resistor $10 ea. F.O.B. Nashville

REPLACE TUBE -TYPE AMPLIFIERS IN YOUR COLOR CAMERA

WITH INTERNATIONAL NUCLEAR ALL -TRANSISTORIZED PREAMPS

MODEL TCA7 is designed specifically for the RCA TK-41 color camera chain and replaces mechanically and electrically tube -type preamplifiers.

ELIMINATE MICROPHONICS REDUCE NOISE REDUCE HEAT

GET HIGH GAIN -BANDWIDTH PRODUCT GAIN STABILITY

Model TCA7 can be installed in about thirty minutes. Mounting dimensions and hardware identical to replaced tube amplifier. Can be powered by TPS7 solid state power supply or directly from the 280 volt camera supply by using a model TR7 dropping resistor with each TCA7.

Write for complete information and specifications to Dept. T -7 INTERNATIONAL NUCLEAR I ;r CORPORATION 608 Norris Ave. Nashville. Tenn. Phone 254 -3366

NUCLEAR CORP.

December, 1963 Circle Item 1) on Tech Data Cord 23

www.americanradiohistory.com TO RUN CIRAIT

OP MACNECORDE R 12-VOC ILO -VAC RELAY MAY

110 VAC FROF ACROSS RUE MOTOR

CLOCK

DPDT

svTLH jI o 12 -VDC NORMAL SUPPLY

CONTROL UNIT TAPE RECORDER

who handles the devices which ring the bells for class changes. At KXXX we located a used IBM school clock which operates on an impulse each minute. Excess relays, clock face, gears, and power supplies were removed and only the inner working parts were in- stalled in the control room. This clock employs "time combs." The appropriate "tooth" is removed for operation on the desired day of the week, and time. In the working mechanism of the clock is a set of fingers (which you can read) that determines the day -whether morn- ing or afternoon-and the time in hours, tens of minutes, and minutes. It has six switching contacts. Each r minute, the time drum ratches and It's a special blend of excite- con Tube. Telescript has been tries to move forward. If the time ment and experience combined selected as exclusive distrib- fingers do not match the broken out to form a rare 6 year old brew utor fcr this quality I. O. Tube. teeth of the time comb, the time known as Telescript. The Shibaden tube matches wheel will not advance. At the time when they do match, the clock In recent months a totally and exceeds the performance wheel moves past the fingers and new management team has and warranties of its competi- closes all six contacts for approxi- been selected to direct and tors...yet it costs 25% less! mately 30 seconds. We use Magna - operate Telescript. A number In coming months you can corder PT 6's for recording. When of important developments lock forward to a number of the clock "fires," a 12 -volt relay is closed, as shown in the diagram. have taken place... new prod- important announcements If the recorder is in the record ucts and services are being from Telescript. Meanwhile, mode and forward position it will added and developed to com- please write and ask for more start, causing voltage picked up plement and expand the deailed information about the across the run motor to be applied Telescript product line. Sh baden L O. Tube. to a 110 -volt relay which locks the Among the new products is machine in run position. At the of the 30- second im- the Shibaden 5820 Image Orthi- end pulse from the clock, the 12 -volt relay will open. However, the 110 - volt relay maintains the recorder running until the forward switch is moved to "stop." The clock is so 1 arranged that it can be set up to control a complete week's recording schedule. At KXXX, we have the clock set `I[9114á 11- 411-4.1 CIRIPT INC 0 to start the recorders about 40 sec- \\2_ 6505 WILSHIRE BOULEVARD., LOS ANGELES, CALIFORNIA 90048 onds ahead of time - and it has been holding very steady. Circle Ile' 11 on Tech Data Card 24 BROADCAST ENGINEERING

www.americanradiohistory.com January SUBJECT REFERENCE INDEX -1963 10... World's Largest, Most Power- ful Radio Station 12... Remote Pickup Broadcast Antennas 16 ...Effects of VSWR on Sterco AM RADIO July - 10, 12. 16 May - 34 Jan 10, 12, 19, 22 Aug - 16, 20 Sept - 10 Separation - Sept 12, 20, 28. 36 Feb - 17, 22, 26. 36 - REMOTE PICKUP 14 ...Techniques for Using RG- March - 20, 24 Nov - 14. 34, 48 17/U Coax April 12. 16, 22 Jan - 12 - ETV May 24 June - 32(EE) 19 ...The Hot Water Tank at - Oct 30(EE) June 14, 28 Feb - 32 - WJIL - Oct 18 July - 10, 14, 28 - STEREO Locating Directional Antenna Aug 12, 20, 34 22... - FCC RULES Jan 16 Sept 20, 26, 28 - Systems - Feb 10 Oct 26 Jan - 22 - - May 16 28(EE). . . Dark Neon Lamps Nov - 34, 36, 48 Feb - 10, 14 - March - 13. 24 Aug - 10 28(EE).. . Correcting Recorder ANTENNAS April - 12, 22 Sept - 16. 20 Echo Dec 8, 10, 16, 18, 20 Jan - 10, 12, 16, 19, 22, May - 23 - 28(EE). .. Detuning an Idle Broad- 28(EE), 30 Aug - 10. 12, 34(EE) Sept 10, 20 STUDIO & FACILITIES cast Tower Feb - 10, 26, 32, 36(EE) - PLANNING March - 18 FM RADIO 30... Series and Shunt Fed Anten- April 22 Jan - 22 - Feb 10. 32 nas May 24 Jan - 16 - - April 14 Aug - 24, 28 Feb - 10 - February Sept 14 May - 16 June - 14 STL Remote Control Systems - July 14 10... Oct - 18, 26 Aug - 10 - Aug 12 for FM Sterco and SCA Dec - 16 Sept - 10 - Nov - 42 Oct - 18 12 ...Full Spectrum Television via AUDIO Dec - 8, 10, 16, 20 Nov - 42 Dec 16 CATV Feb 17 - 8, - INDUSTRY FEATURES May 16, 34 14... Practical Applications of - March 32, 35, 48 RADIO SYSTEMS & June - 10, 16, 24, 28, 32(EE) - OPERATION FCC's Engineering Rules July 12. 26(EE), 28 April - 18 - Jan 10, 12, 19, 22 17 ... Automatic Music System Aug - 16 Dec - 20 - Sept 28 Feb - 10, 26 22... Accurate Intensity Measure- - March 20, 24 Nov 14, 36, 40(EE), 41(EE) LOGS - ments in Ambient Fields - April 12, 16, 22 Dec 18 March 20 - - - May 16, 24 26 ... When To Use A Unipole Aug - 34(EE) - CARTRIDGE TAPE Nov 48 June - 14, 28 Antenna Design - July 28 Feb - 17 - 10, 14, 32 ... A Low Cost Instructional March - 44(EE) MAINTENANCE Aug - 10, 12 April 30 Jan 14. 28(EE) Sept - 10. 16 Television System - - Oct 26 June - 18 Feb - 22 - 36(EE). . Automatic Power Aug - 20 March - 44(EE), 46(EE) Nov - 48 Change System Nov - 40(EE) April - 16 TECHNIQUES May - 20, 34(EE) March CATV June 20 Jan - 14, 22, 28(EE) - 22 13 ... The Practical Application of Feb - 12 July - 10, 14, 16, 20. 26(EE) Feb - Oct 14 Aug 14, 34(EE) March - 24 FCC's Engineering Rules - - April 12. Sept - 14 - 14, 16, 22 16 ...A Transistorized Television CONSTRUCTION & Oct 16. 26 May - 16. 20 MODIFICATION - Monitor Nov - 18, 36. 40(EE) June - 20 Feb - 17, 36(EE) Dec - 12, 18, 22(EE) July - 20 18 ... Mechanical Aspects of An- March - 44(E)). 46(EE) Aug - 10, 12, 14. 28 tenna Towers May 28, OFF /AIR & RELAYS Oct 16, 24, 26 - 34(EE) - New System for Automatic June - 18, 24, 32(EE) Aug - 12, 28 Nov - 18 20...A July - 26(EE) Dec - 10 Program Logging Aug 20, - 34(EE) PROOFS TELEVISION 24 ...Interpreting FCC Interference Sept - 34(EE), 35(EE), 36 April - 22 Oct - 24, 30(EE) May - 20 Feb - 12, 32 Rules Nov - 26, 34, 40(EE), June - 20 March - 18, 28 28 ... High- Powered UHF Televi- April 14 41(EE), 42 Aug - 10 - sion Dec - 22(EE) Oct - 16 May - 28 Aug - 14. 28 32...A Profile of the NAB Engi- DESIGN RADIATION & Sept - 12, 34(EE) neering Department March - 16 PROPAGATION Oct - 14, 18, 20, 24, 30(EE) Nov 12. 20, 26 35 ...Special NAB Show Section June - 10 Jan - 16, 19, 28(EE) - July 12 48...IEEE Show Section - Feb - 22, 26 TRANSISTORS Aug 16 - March 24 . Winding for - March 18 44(EE).. Reels Tape Sept 12, 28 April 12, 22 - - - May 28 Cartridges Nov - 4 Aug 14 - - June 32(EE) Oct - 26 - 44(EE) ... Rain Shields for Bowl ENGINEERING THEORY Sept - 12, 28. 36 Insulators Jan - 16, 30 RECORDING (AUDIO) Nov - 14 Feb 26 44(EE) ... Reducing Delay Time in - Jan 28 TRANSMISSION LINES March 18, 24 - Thermal Relays - Feb - 17 Jan 14 April 12, 16 - - March 20, 44(EE). 46(EE) Feb 12 46(EE). Cueing Protection for May 16. 24, 26 - - .. - April 30 March 28, 44(EE) June 16, 28 - - VU Meters - May May 26 July 26(EE), -16 - - 28 June 18 April Aug 24 - - Aug - 20, 34(EE) TRANSMITTERS 12... Suppression Practices for Sept - 16 Nov 34, 36, 40(EE), 48 Jan 10 Oct 14. 20 - - Broadcast - Dec - 22(EE) Feb - 10, 32 Stations Nov - 20 March 28 14... Lighting for Your TV Studio Dec 10 RECORDING - - (VIDEO) April - 12 16 ...Spectrum Display in Broad- Sept - 34(EE) May - 34(EE) EQUIPMENT Oct - 30(EE) June - 28, 32(EE) cast Monitoring Feb 17 - Nov 12, 20, 26 July 20, 26(EE) 18.. . Touring the NAB Exhibits March - - - 16. 20 Aug - 10 22 ... A Plan for Making Antenna May - 28, 34 REMOTE CONTROL Sept - 10, 20 June - 10, 24, 32(EE) Feb - 10 Oct - 16. 18 Proofs www.americanradiohistory.com 30... Cartridge Tape at Work 1 6 ... Planning for Automation May 20...A Review of Automatic I 6 ... A New Method of Stereo Transmitter Logging Broadcasting 28 ... Transistorized Audio Distri- 20... When the Proof-of- Perform- bution System ance Fails 34(EE).. . VTR Guide Height Ad- 23 ... Twelve Rules for Dealing juster With the FCC Inspector 35(EE) ... Weekend Case Makes 24 ...Theory of Directional An- Remote Kit tennas 36...A Transistor Power Supply 26...A Review of Transmission , October Lines 14... Analyzing Cascaded Ampli- 28 ... The Economy Video Switcher 34(EE). .. Auxiliary Console Moni- fier Systems I 6 ... When the Proof-of- Perform- ORGANIZE - IDENTIFY tor 34(EE) ... Diode Distortion ance Fails PERSONAILIZE...WITH 18 ... Transmission Systems for 34(EE).. . Stepper Relay ETV os expo 'ew I °' I r' Bitures June 20... A Proposed Television Center full 44 character wheel, interchangeable actes 10... Audio Level Devices 24...A Copying System for News sory wheels vertical horisontal lettering. or 14...Planning a Modern Studio Slides 16... Design of Resistance -Coupled 26 ... Directional Antenna Phasing Audio Amplifiers 30(EE) ... Microwave Intercom Fa- 18 ... "Roll Your Own" Automatic cilities Tape 30(EE) . , . Automatic Record Tip 20. .. When the Proof-of- Perform- Projection Control ance Fails 24 ...A Microphone Filter November . . . Re- 28.. . Grid Modulation, Theory and 12 (cover feature) Color Techniques cording at the Networks 32(EE) ... Remote Amplifier 14 ... Audio Level Devices 32(EE) ... Automatic Reclosure I 8 ... Transistor Amplifier Servic- July ing Techniques 10...A Test Equipment Check List 20... Television Tape Techniques 12 ...Audio Level Devices Today 14 ... Broadcast Station Spare Parts 26... Variable Wind for the TR -11 Inventory 34...A Low Cost Tape Delay Sys- 16 ...Specialized Test and Measur- tem ing Instruments 36... Updating Audio Reproducing 20... Maintenance of a Small TV Equipment Studio 40(EE) ... High Response Boost 26(EE) ... Auto Speaker Muter 40(EE) ...Cartridge Unit Speed Ac- 26(EE) ... Modulation Peaks curacy 41(EE) ... Portable Utility Test 28.. . Acoustics in Broadcasting Speakers August 42...A Circular Broadcast Console 10.. . FM Stereo Proof-of- Perform- ance Measurements Desk 48 ...Transcribing Off /Air with 12.. . AM /FM Relay Network Techniques Dictating Equipment HAND EMBOSSING TOOL 14... Tracing Television Interfer- December Model M -29 $4995 ence 8 , , . Planning the FM Stereo In- 16. .. Audio Level Devices stallation 20...A Rotating Tape Cartridge 10 ... Measuring and Monitoring Rack the FM Stereo Broadcast 24 ... Frequency Versus Wave- 12 ... When the Proof-of- Perform- length Calculations ance Fails 28 ...Television Off /Air Pickups 16 ... Antennas for Stereo Broad- 34(EE). . . The Third Log casting 34(EE). . Updating the Model 300 18 Checking of Audio D'NO INDUSTRIES, INC. ...Phase ]ept. BE P.O. Box 1030, September Channels Berkeley 1, Cal turnia 10... Remote Control of Broadcast 20 ... Stereo FM, Past, Present, Transmitters and Future 12...A Transistorized Cross -Bar 22(EE) ... NIAC Receiver Video Switcher 22(EE) ... High Line Voltage 14 ... RF Ammeter Calibration 22(EE) ... Jack Field Labels Tests 22(EE) ... Preset Recording Clock Circle Item 14 en Tech Data Card 26 BROADCAST ENGINEERING

www.americanradiohistory.com Antennas for Stereo mounted and properly matched to (Continued from page 16) the transmission line, the VSWR hearing only this channel would and multiplex characteristics will Now There Are hear a full and complete transmis- be as specified. sion consisting of both audio chan- However, there is a growing ten- TWO New nels. The 38 -kc subcarrier is modu- dency among broadcasters to mount lated with the difference between FM antennas on the side of existing FAIRCHILD the left and right signals. It is in- towers, rather than on a pole at teresting to note that the sum sig- the top. Basically, this practice is TURNTABLES nals are allowed a maximum of sound from an engineering point 45% modulation, as are the differ- of view, and has much to commend Built to ence signals. The pilot tone, which it. But, one very important point is transmitted to synchronize the must be considered when a side - receiver detector, may have 10% mounted antenna is used for stereo: Surpass the modulation. Cross modulation re- The presence of a tower near the fers to modulation products in the antenna will distort its pattern, and Proposed transmitted signal caused by un- cause deterioration of the VSWR. wanted signals and coupling in the This could increase VSWR to 1.5:1 NAB transmitter, and by reflections in or even more! the transmission line and antenna. Considering the effects of un- Standard! In other words, this crosstalk can stable VSWR further, let us con- be caused by the L+R main chan- sider the signals that we are trans- nel modulation somehow phase mitting. The basic FM emission has For over a quarter of modulating the 38 -kc L -R sub - many sidebands, but they have this a century carrier. in common - they are above and FAIRCHILD VSWR below the carrier frequency and Turntables have The August, 1961 issue of 90° out of phase with each other. If continued to BROADCAST ENGINEERING the phase relationship among these provide, carried an article on measuring through radio sidebands changes, or if they are stations of VSWR in stereo FM transmitters. attenuated or amplified unequally, the world, Some of the results are of great the result will be crosstalk-through the finest importance and arc worth restating record amplitude modulation of the FM reproduction. To here. The author's main conclusions signal. For satisfactory freedom meet the demands of are that crosstalk increases as an- from crosstalk, spurious modulation the new proposed NAB standard and tenna and line mis- stereo broadcasting, FAIRCHILD pio- transmission components should be at least 40 neered the use of belt drives for profes- match becomes greater. If this con- db below the signal level. sional turntables as exemplified in the dition occurs, the listener can retune FAIRCHILD Model 750 -the only 3- speed, Other Troublemakers 16" turntable with -65 db rumble, and improve his reception slightly. .03% wow and flutter, 3 speeds easily This means that receiver tuning One last item that can cause selected, whisper soft operation, cue pad will mask the results of VSWR trouble in stereo FM is the device provided, and minimal moving parts for changes -even fairly great changes. that couples more than one trans- long trouble -free performance. Since the natural tendency of the mitter to the same antenna system. listener would be to change the A few combination FM -TV instal- tuning of his receiver to maintain lations use equipment in which a AND now join- ing the 750 acceptable quality and level, it third signal (FM) is added to the is the new would seem that antenna and trans- two TV signals (audio and video) FAIRCHILD mission line stability are not of for transmission via the same an- Model 755 -a 2 -speed belt very great importance. This is far tenna. This is accomplished by drive profes- from true; because, as the VSWR adding another arm to the diplexer, sional turn- thus making it into a hiplexer. This table. The 755 rises, the problems of maintaining incorporates proper control of the signal become can be done only if the TV signal extremely low very great. is in the low band - channels 2 rumble and im- a perceptable wow The SWR for satisfactory opera- through 6. Such system offers a and flutter with fast -cueing combined tion of stereo FM should not ex- considerable savings, but it can also with attractive packaging and easy ceed 1.1:1, over the nominal band- lead to troubles if stereo FM is in- installation. The low price of the Model 755 allows every radio station to step width of 200 kc. This requirement volved. There is the risk of changes up to quality for today's quality con- is far more stringent than for mono- in VSWR, or uneven attenuation of scious listeners. phonic FM, which often works with upper or lower sidebands in their Write to FAIRCHILD - the pacemaker in a VSWR as high as 1.5:1 or 2:1. passage through the diplexer or tri- professional audio products - for com- Most FM antennas will come plexer. If you are responsible for plete details. from the manufacturer carefully the operation and maintenance of matched to the center frequency, such an installation, take particular FAIRCHILD so that the operating bandwidth care to check impedance match of RECORDING EQUIPMENT CORPORATION will be satisfactory for stereo. Pro- the line and antenna to the FM 10-40 45th Ave., Long Island City 1, N.Y. vided such antennas are top system. Circle Item 29 on Tech Data Cord December, 1963 27

www.americanradiohistory.com From Monitoring and Measuring THE Translator Company (Continued from page 11) stereophonic subcarrier sidebands. A 45° shift along the pilot wave would completely destroy separa- NOW AVAILABLE: tion in a properly aligned receiver (Fig. 7). If you continue to shift the 38 -kc sidebands another 45° along the pilot wave, you again see All the signal in Fig. 6, except the Fig. 7. Subchannel only, 45 ` out of phase; about pilot synchronized method monitoring. right and left channels are reversed. of Physically, of course, the right and As yet there is no commercially extra left audio lines from the studio have produced equipment suitable for not been changed in any way. The control room monitoring. The os- pilot synchronized method of moni- cilloscope bow-tie and pilot-syn- TV toring will tell immediately if such chronized methods may be used a reversal has occurred, whether in the control room as a stopgap, the oscilloscope connections are re- and should be understandable even Coverage versed or not. to combination operators. Stereo- Operational Considerations phonic broadcasting is moving out and We have examined methods for of the purely technical "Now I'm monitoring and measuring the FM on the left, now I'm on the right" stereophonic signal with meters and stage and into the more artistic fill in with an oscilloscope. I would like stage. It is rapidly becoming neces- to draw a distinction between moni- sary that a good operating monitor toring during operation and during - employing meters - be devel- via testing. When you are checking the oped to aid stereo in becoming an stereo signal (presumably during the integrated tool within the station's experimental period), you can use programming framework. Translators sine-wave audio signals and take Desirable Features your time to examine each signal Let's re- examine, in the light Write today for your Plan- separately; you are primarily inter- of another year's experience, what ning Package from EMCEE, ested in measuring exactly how the should be included in an operational the Translator manufac- transmitting equipment is working. monitor. For quantitative alignment turer with more experience That is, you can take the time to or proof -of- performance purposes, properly measure phase and ampli- we should be able to monitor the and more models .. . UHF tude excursions. However, during following, as a minimum: (1) right VHF ... 1 watt to 100 watts. regular program transmission you channel amplitude, (2) left channel are more interested simply in amplitude, (3) main channel ampli- whether the system is working tude, (4) subchannel amplitude, (5) properly. Indications of modulation total composite amplitude, (6) pilot and balance must be easily observ- subcarrier amplitude, (7) crosstalk able by the control room operator, into the subchannel, (8) crosstalk who usually has many other re- into the main channel, (9) phasing sponsibilities to carry out simul- between the pilot subcarrier and taneously. the stereophonic subcarrier side-

EXCELLENT! ©LECTRONICS, For "Beeper " Level ing, Studio Intercoms. Paging, P.A.. [MISSILES AND Cue Amplifiers. etc. AUTOMATIC GAIN CONTROL AMPLIFIERS EIOMMUNICATIONS, INC. BRAND NEW government surplus. Highest quality 160 E. Third St., Mount Vernon, N. Y. Components well overrated. No electrolytics. Fuit 10550 914-668-3012 schematic clearly printed on bottom plate. Oper. Gentlemen: ating power 107120 VAC, 50-60 cys. TYPICAL SPECS -INPUT LEVEL: -20 to .10 dbm for out put constant within 2 db, or with a simple modification, -40 to -IO dbm. POWER OUTPUT -full Please send your "TV Coverage Plan- 4 watts. INPUT Z 75. 150. 300 or 600 ohms balanced. OUTPUT Z: 200 or 600 ohms C.T. FREQUENCY RESPONSE - within 2 db 200 -5000 cps. Gives excellent voice quality. NOISE AND ning Package." NUM -down 50 db below full output. TUNES -1 ea., 5Y3, 6H6, 6517, 65117, and 6V6. Amplifiers arranged for plug in mounting. If desired. they can be remounted on rack panels (2 per panel) and plugs replaced with barrier strips.(No rack shelves available at the time) Input and output also appear with insulated phone jacks on front panel. This type currently in use at stations in- Nam, cluding the top rated San Francisco radio station. TERMS- 119.95 ead,...Cash, check or money order, shipped freight collect, F.O.B. Limited quantity. Price subject to change without notice. Addr,,s City _Stat ENGINEERING] 2175 411h Avenue San Francisco 16 SEI 9197 Circle Item 15 on Tech Data Card Check Hem 59 on Tech Data Card

28 BROADCAST E N G I N E E R I N G

www.americanradiohistory.com bands, and (10) pilot subcarrier frequency. A monitor should be capable of indicating as many of HERE'S EVERYTHING YOU WANT! these characteristics as possible dur- ing normal program transmission. Now, let's look at what the con- THE trol room operator should observe during operation. Since there are - in effect - two separately con- NEW trolled and modulated channels, there should be at least two meters. ?Z ognecord The two meters may indicate either left and right channels or main and MOrl_1 subcarrier although 028 channels, the former may be easier for most op. RECORDER / REPRODUCER erators to compare readily with FOR TWO -TRACK STEREO OR MONAURAL actual programming. A third meter HALF -TRACK OPERATION should be included to measure the TAPE SPEED: 7.5 and 15 inches per second total composite signal whether REEL SIZE: 5 -, 7 -, and 10312 inch - HEADS: Selectable Erase, 2- Channel Record it be a peak indicating, absolute and 2- Channel Play reading, or an algebraic summing PRICE: from $995 meter - to eliminate mental arith- Here is unquestionably the finest tape metic. recorder Magnecord has ever offered Mention of SCA transmissions the professional audio field. Important has been left out, not because they advances in the Model 1028 include are unimportant to some FM opera- new MICRO -OPTIC heads and new tors, but because they should right- electronics for wider, flatter frequency response, better signal to noise ratio, fully be measured with separate and lower distortion. Equalization equipment. factory- adjusted to N.A.B. standards, or adjustable to other than standard Conclusion equalization. For the best recorder any amount of money can buy, it's the I have tried to provide a few Model 1028! methods by which the stereo FM write today for complete specifications broadcast may be monitored during program transmission (or measured MAGNECORD Sales Department during the experimental period) in MIDWESTERN INSTRUMENTS the hope that more stereo FM sta- P. 0. BOX 7509 ; TULSA, OKLAHOMA 74105 tion operators will be able to pro- vide a good signal to the listener. I have also pointed out a few con- siderations that the designer of FM stereo monitoring equipment should take into consideration. The instru- ments that result will help the sta- tion operator provide the best FM stereo signal feasible -so that now, after over two years of broadcasting in the new medium, we can devote more effort on presenting the artistic values that are available to us.

Fig. B. Broadcast of recorded right chan- nel signal with the pilot sync method. Circle Item 16 on Tech Daia Cara December. 1963 29

www.americanradiohistory.com Barger NEWS OF THE INDUSTRY

AM and FM Operator Rules Amended The FCC has issued Memorandum Opinion and Order (Docket 14746), reaffirming and modifying its decision of July 15 regarding operator require- ments for AM broadcast stations with power of 10 kw or less which use non - directional antennas, and FM broadcast stations with transmitter power output of 25 kw or less. The action results from petitions for reconsideration and oral argument filed by the National Association of Broadcast Employees and Tech- NEW nicians. The rules require stations to employ, for routine transmitter operation, persons holding at least radiotelephone 3rd-class operator permits endorsed for SIMPLE METHOD TO LOG employment at broadcast stations. Stations using these operators may employ, under certain conditions, a supervisory engineer holding a radiotelephone 1st - TRANSMITTER READINGS class license on a contract part-time basis. The new operator rules become effective Jan. 1, 1964. A transitional period from that date to April 19 during The Bauer "Log Alarm" is which stations may utilize the services of restricted radiotelephone operator simple ... accurate ... easy permittees for routine transmitter operation. After April 19, 1964, the operation must be handled by persons holding at least radiotelephone 3rd -class operator to operate . .. permits better permits endorsed for employment at broadcast stations. During the transitional use of your manpower . .. period, stations may not hire radiotelephone 1st -class operators on a contract meets all FCC requirements for part -time basis unless at least radiotelephone 3rd -class operators with broadcast automatic logging devices ... endorsement are employed for routine transmitter operation. To obtain a all in 101/2' of rack space. broadcast endorsement for the radidotelephone 3rd -class operator permit, it will be necessary to pass a written examination. Information concerning the new Complete Details Available on Request! examination will be contained in a Public Notice.

ELECTRONICS C O R P O R A T I O N 1663 Industrial Road, San Carlos, California Area Code 415 591 -9466 Circle Item 17 on Tech Data Card

SPOT MASTER

Tape Audio Expert Visits U. S. TV Equipment for World's Fair Percy Wilson, technical editor of Gram - International Nuclear Corp. has manu- Cartridge aphone magazine and Britain's foremost factured, tested, and readied for ship- authority on high fidelity, combined a ment thirty -eight video /pulse distribution recent personal visit to this country with amplifiers for the TV center of the New Racks an inspection tour of several high fidel- York World's Fair opening in April of ity manufacturers whose products are next year. The equipment was ordered marketed overseas. Wilson is shown here by New York Bell Telephone, who is looking over the shoulder of Roger An- charged with all World's Fair communi- derson, manager, Research and Develop- cations, including live TV relay for ment Section of Shure Brothers, Inc., as nationwide color broadcasts. According Anderson runs a tracking capability test to Raymond Weiland, president, Inter- on one of Shure's Stereo Dynetic high national Nuclear, these special amplifiers fidelity cartridges. Also an interested ob- will allow the Bell Company to use . from server is Mrs. Wilson, who accompanied many more TV circuits simultaneously industry's would ordinarily be possible. Gene most comprehensive the noted technical expert on the trip. than line of cartridge tape equipment. Enjoy finger -tip convenience with RM -100 wall -mount racks. Store 100 cartridges in minimum NEXT MMONTII space (modular construction per- Issue mits table -top mounting as well); Annual Antenna - sections $40.00 per rack. Extra rack for UHF Plus: available at $12.90. Spotmaster Radiators Lazy Susan revolving cartridge rack Design of Directional Antennas Engineer's Exchange, Book $145.50. holds 200 cartridges. Price: Introduction to Television Translators Reviews, News of the Industry, Write or wire for complete details. Antenna Matching Network Design New Products, and many 111 Remote Pickup Transmitter other important items you'll ? want to read! BROADCAST ELECTRONICS, INC. After the Freeze, 8800 "`Brookville Road Reserve your issues! Fill out and send in the convenient subscription card bound in Silver Spring, Maryland this issue, and receive the Broadcast Engineers' Maintenance Guide-absolutely FREE! mow Circle Item 18 on Tech Data Card BROADCAST ENGINEERING 30

www.americanradiohistory.com Alignola, engineer in charge of the in- Color Film On Tape Use FM Station Increases ERP stallation at the Fair for New York Bell, A 16mm color film on magnetic record- The FCC recently granted permission said that the equipment was chosen be- ing tape is available from the 3M Corn - for KNIK -FM, Northern Television, cause it is transistorized, light and corn- pany, maker of "Scotch" brand tapes. Inc., to increase power to 3,000 watts met. allows multiple circuit usage and The 25- minute sound film, entitled effective radiated power. The switch of meets the performance requirements es- "Magnetic Memory," is available on a the equipment was made at midnight tablished by his company. free -loan basis for showings to clubs Sept. 26th. and on the 27th, KNIK -FM and other organizations. This profession- began broadcasting with a new Collins FM Net to Carry ally- produced film is built around the transmitter. The actual transmitter National Programming theme that magnetic tape has added a power is 1,000 watts as compared to "new dimension" to the memory of man the previous 250 watts. However. the QXR recently became the nation's new- by providing a new method of record- power gain of the antenna gives KNIK- est interlinked radio network, when it ing and preserving his knowledge, skills, FM an effective radiated power of 3,000 began transmitting live from coast to and creative efforts. Opening with a watts. In the past, effective radiated coast, it was announced by James Sond- non -technical description of the theory power was 750 watts. The transmitter is heim, president. Twenty -one years have of sound and recording, the movie ad- transistorized with the exception of the elapsed since the youngest of the four vances through the many uses of tape, power tubes and is completely equipped other major radio networks, ABC, was from capturing a baby's first words to for stereo broadcasting. established. QXR affiliates in major preserving the technical data of a SMPTE markets from New York to California manned space shot. Award will carry five hours a week of topical Robert L. Lamberts, research associate interview and discussion programming. TV Equipment Ordered with Kodak Research Laboratories, has A program of business news and anal- The General Electric Co. announced re- won the 1963 Journal Award of the ysis is expected to be added to the ceipt of one of its largest orders for Society of Motion Picture and Televi- schedule. Stereo FM music and drama television studio equipment from a single sion Engineers. SMPTE Editorial Vice - series will be distributed to affiliates on station, in a contract for over $700.000 President Herbert E. Farmer announced tape to maintain the network's reputa- from WWJ -TV. The Detroit News Sta- the award, which recognizes the most tion for broadcast standards of the high- tion is engaged in an extensive, two -year. outstanding technical paper published in est quality. Interconnection of the QXR $1.2 million expansion and moderniza- the monthly Journal of the SMPTE dur- network, which is owned by the Novo tion program. The order covers studio ing the preceding year. Mr. Lamberts's Industrial Corp., represents a "major and film cameras, control systems, audio winning paper. "Application of Sine - step in the evolution of FM as a cul- systems, and monitoring equipment. In Wave Techniques to Image Forming tural medium," Sondheim said. He dis- the order are included eight 41/2" image - Systems," discusses the derivation of closed the network's decision was influ- orthicon studio cameras. two new four - spatial frequency -more properly called enced in part by the results of three vidicon color film camera systems, a modulation transfer function -and illus- nation -wide surveys conducted for QXR remote -control studio vidicon camera, trates uses in evaluating optical and by Media Programmers. Inc. and three special audio systems. photographic systems.

e M MICROPHONES PLAYBACK TAPE MACHINES CONTROL ROOM REVERBERATION

SATISFYING THE HIGHEST QUALITY DEMANDS CF BROADCAST TECHNOLOGY

AUDIO CORPORATION 2 WEST 46 STREET, NEW YORK 36, N. Y. 212 -CO 5 -4111 (r M T) In Canada: J- Mar Electronics Ltd., P.C. Box 158, Don Mills, Ontario CATALOG ON LETTERHEAD REQUEST

Circle Item 19 on Teel Dala Card

December. 1963 31

www.americanradiohistory.com Meredith L. Koerner is now the direc- PERSONALITIES tor of engineering for Radio Liberty. The appointment was announced by Howland Clifford Warner has been named man- H. Sargeant, president of the American COMPLETE ager of the southeastern district sales Committee for Liberation, which spon- office of Eitel- McCullough, Inc., Louis sors Radio Liberty's freedom broadcasts. RADIO AND WIRE Martin, director of marketing of the elec- Arthur J. Kjontvedt was named vice - REMOTE CONTROL tronic tube manufacturing firm, an- president of marketing by the Houston SYSTEMS nounced. Fearless Corp. board of directors, it was P. A. Rasmussen, president of Viking announced by President F. C. Mehner. of Minneapolis, Inc., announced the ap- C. J. Tevlin has accepted an assign- pointment of Ansel Kleiman as general ment as director of the Motion Picture manager. Services Div. for Superscope, Inc., ac- John S. Kane, vice -president and gen- cording to Joseph S. Tushinksy, presi- eral manager, has announced the ap- dent. Tevlin will handle the introduction pointment of H. Grignon as manufactur- to the film industry of the new Super - ing supervisor of the Reeves Soundcraft scope wide- screen motion picture process. Div. of Reeves Industries, Inc. Appointment of Wendell C. Morrison as chief engineer, Radio Corporation of America's Broadcast and Communica- tions Products Div., was announced FOR -1 recently by C. H. Colledge, division vice - president and general manager. In his FM BROADCAST new assignment, Mr. Morrison will direct TRANSMITTERS overall engineering activities for the Divi- sion and its product line, which includes CONTINENTAL'S radio and television broadcast equipment, microwave communications systems, sci- TYPE MR1C entific instruments, two -way mobile radio, marine radio equipment, and audio visual MONITOR RECEIVER products. MOSELEY ASSOCIATES INC. GPL Division, General Precision Aero- Monitors transmitter space, has named J. Frank Price, presi- P.O. Box 9192. SANTA BARBARA. CALIF. dent of the company's Pleasantville In- operation at studio location TELEPNONEAREA CODE 805 967 -1489 OR 967-8119 strument Corp. subsidiary. Indicates Circle Item 20 on Tech Data Card The Distributor Products Div. of In- relative field Telegraph ternational Telephone and intensity at pickup point Corp. has appointed Edward J. Carney as manager of advertising and sales pro- motion. He will report directly to the Has audio monitoring division's president. Leonard J. Battaglia channel SPOTMAS'I1ER and will be responsible for all product advertising and related sales promotion programs. Gives warning lamp for Tape Cartridge Vitro Engineering has appointed Don- carrier, buzzer alarm for ald F. Ferguson technical director, re- loss of carrier sponsible for Vitro's operations in India. Winder This was announced by Dr. Norman A. write for details today Spector, vice -president of Vitro Corp. of America in charge of the engineering and services group, who stated that Mr. Ferguson would be headquartered at the Bombay office. PRODUCTS COMPANY Sylvester L. (Pat) Weaver, Jr. has been BOX 5024 DALLAS 22, TEXAS TELEX CEPCO appointed president and chief executive 65í'P9 Subsidiary of Ling- Temco.Vought, Inc. officer of Subscription Television, Inc. Circle Item 39 on Tech Dota Card The new Model TP -1A is a rugged, dependable and field tested unit. It is easy to operate and fills a need in every station using cartridge equipment. Will handle all reel sizes. High speed winding at Seaa Precision Antennas 22! " per second. Worn tape in old cartridges is easy to replace. New or * OFF- THE -AIR PICKUP - FM or TV old cartridges may be wound to any * LOW POWER UHF, VHF TV TRANSMITTING length. Tape Timer with minute and second calibration optional and * STL AND TELEMETERING ANTENNAS extra. Installed on winder or avail- able as accessory. TP -1 A is $94.50, Engineered to meet rigid FM and TV station specifications, with Tape Timer $119.50. and to endure the tests of weather and time. Write or wire for complete details.

Built to your specifications by 2814 19th BROADCAST ELECTRONICS, INC. STREET 8800 Brookville Road SCALA RADIO CORP. SAN FRANCISCO 10 Silver Spring, Maryland VA á2e98

Circle Item 21 on Tech Data Card Circle Item 13 on Tech Data Card 32 BROADCAST ENGINEERING

www.americanradiohistory.com What Station Men are saying about THE RCA "TRAVELING WAVE" ANTENNA

sb u r g At h Spartansburgt an M T eenville, Parker Po/and sheville, Gr says: Springs, Asheville, President, with the d and the Qn Chief n Me WLOS-TV, well satisfied our Travelling At ll Wolfson, the rcrng conditionseced ar says: TV is extremelyAnnninstallation. d P promis station s s encounteroperation An Wave every the the We tenne Mt ¡ons der é Or Travelling throughoutu operate thVere advantages strength al propertieswe onwithout Mt Washington signal operate electricalreas d area exceeded Wn aside state antenna andrito' irom e 82 -county, very he amom¡' the

At KGIN -TV, Grand Island, Nebraska At KROC -TV, Rochester, Minn. D. Raymond Taylor, Chief Engineer, says: Robert W. Cross, Chief Engineer, says: "Field strength measurements show that the signai "During installation and erection of our Travelling far exceeds the predictions of the FCC 50 ;50 Wave Antenna, I was most favorably impressed Field Strength Curve. Reports from viewers on the fringe with the mechanical simplicity and ease of assembly. area substantiate these measurements. The standing Subsequent electrical check -out of the antenna wave ratio is very good and no ghosting is present." and its 1300 -ft. transmission line proved it to have the lowest VSWR of any system encountered."

At KOAM-TV, tee Paso, Texas y Leo S. Pittsburg, El áave Staff At KTSM-TV, says: we ora Chief Kansas President, Engineer,ansas Wyler, KarlKa O. It has the from s was Antenna. 1959, has scie/ picture KTSM-TV Wavee sa .l believe that December e. "1 TravellingRange Peak since away the RCA Performant an he me s yPh y order on wwith power. t gives to been in service pleasedleased ¡s practicallyradically fewer . tighten, and,cre we bolts to very ewer and We Yes he power in thil no maintenance,Overall \ insPeCtions /

Favorite Antenna of High-Band Stations! CH 7 CH 8 CH 9 CH 10 CH 11 CH 12 CH 13 CJAY KGHL KLRN KROC CHCH KCND CKCO KCMT KSWS KTSM KXTV KCBD KEYC KMSO If you want more facts about this VHF High -Band KOAM WKBT WAFB WCBB KGIN KFVS KOVR Antenna, your RCA Broadcast Representative can WNAC WMTW WWTV WIS WBAL KNMT KS00 help you. Or write RCA Broadcast and Television WPBN WOOD WLBN WLWA KTVH WGAN Equipment, Building 15-5, Camden, New Jersey. WTRF WQAD WPTT KVAR WIBW WXYZ WXGA WEAT WJZ WMEB WLOS WPRO WOKR The Most Trusted Name in Television

Circle Item 23 on Tech Dota Card www.americanradiohistory.com NEW PRODUCTS

Record Compensator A passive record equalizer for stereo and monaural discs, flexibly designed to permit broadcast stations to install new stereo facilities, to convert existing mon- aural facilities to stereo, or simply im- prove monaural performance only, has been introduced by Gray Research and Development Co., Inc. Called the 604 - Sound Tapes Introduced MIS, the unit takes the constant velocity Two professional -quality sourd record- output of either stereo or monaural mag- ing tapes have been announced by East- netic cartridges and feeds the signal into man Kodak Co. Eastman Sound Record- low- impedance microphone channels on ing Tape, Type A303, is basically a low - print tape with a signal -to -print ratio of 54 db. High-frequency sensitivity and un- distorted output, however, have been in- creased 33 %. Type A304 is a high -out- a stereo mixing console, automatically put tape which has more than double R K compensating for both cartridge output the undistorted output capability of con- ventional tapes. Signal -to-noise ratio of PROFESSIONAL TURNTABLES and recording characteristics. The device operates with either high-impedance mag- A304, as measured from zero signal to netic stereo cartridges or low- impedance saturated output, is 79 db. Print -through, 41111:2111k_ monaural cartridges, and is easily inte- has been held to the general purpose L. Quality grated with the present equipment of level of 49 db. The tapes use a polyester Continuous most stations. Mechanically interchange- base and an improved Durol base; the Performance able with the Model 602 -C Equalizer, latter is a modified triacetate approxi- Simplicity widely used by monophonic stations, the mately 40% stronger than conventional control chassis provides smooth switch- triacetate. Lubrication is incorporated Priced from 915.00 to '235.00 ing from mono to stereo discs, as well both within the coating and on the back wear to as to 16" broadcast transcriptions. Two of the tape to minimize head and high- frequency rolloff positions are in- provide quiet tape transport. The tapes cluded for noisy records or instantaneous will be supplied on Eastman Thread - lacquers. Prices are: 604-M /S, $137.50; Easy Reels, which have a built -in splicer. 604 -M (monophonic only) $79.25. Circle Item 39 on Tech Do.a Card Circle Item 32 on Tech Data Card Why Repair Your Old Capstan Drive Motor When You Can Buy a New One

CONCERTONE tape recorders FOR

Full track - -or Stereo Width 19' for rack mounting -also portablè ONLY Professional broadcast quality. Grounded Audio Connectors fond for prices and !!erofr. A series of audio connectors, featuring $12000 a ground terminal with continuity to the connector shell, is now available from Switchcraft, Inc. The "Ground Con- Now you can re- tactor," as it is called, is additional to place your old and the three circuit contacts, and automati- worn Ampex drive cally grounds the mating connector shells assembly with a STANDFORD -OMEGA completely new upon engagement. Also, any of the three motor, for the same money it would cost Condenser Microphones circuit contacts can be grounded simply you to repair your old one, and get added by connecting a jumper (provided) to performance features such as lower flut- '130.00 to 5150.00 ter, cooler running and higher torque. The shell or ground. Another new feature new hysteresis synchronous Capstan Drive of the cord plugs is a "captive" insert Motor by Lang Electronics is the direct Viking Tape Recorders Superes Headphones screw which cannot be lost during cable replacement for any Ampex model 400/ unit. New heavy duty Cap- Kwikheat Soldering Irans installation. Each connector, formed of 350/351/354 stan Drive Motor from Lang Electronics diecast zinc alloy construction with a saves you time and money and provides Send for literature. satin nickel finish, uses a dielectric in- you with years of trouble -free perform- FAST FAST FAST Service sert of thermosetting plastic with high ance. Two models available: two -speed impact resistance. The connectors, series Model AM -2 (71-15 i.p.s.), or three -speed Sh n,enl by Moto/ heist, Air bewail, of parcel Post Model AM -3 (32-71-15 or 71-15-30 i.p.s.). A3F, A3M, B3M, and C3M, are latch - Model AM-2: $120.00. AM-3: $145.00 Electronics Mfg. locked to prevent their pulling loose 'RUSSCO from the cable, and are provided with Order direct from 6879 No. Sunnyside Clovis, California dual pressure plates for strain relief and LANGELECTRONICS INC. Ph. 299 Area code 209 -4692 a secure cable lock. 507 FIFTH AVE., N.Y.17 Circle Item 22 on Tech Data Card Circle Item 33 on Tech Data Card Circle Item 30 on Tech Dafa Card 34 BROADCAST ENGINEERING

www.americanradiohistory.com Stereo Installation (Continued from page 9) ably will be necessary to purchase 1'1.\lN\l a new exciter and, of course, a ALTEC stereo generator. A MUST FOR Since stereo listeners arc a dis- for recerdmg aid tru;+a:st studies criminating and critical audience, EVERY RECORDING & audio equipment should be chosen with care. It will be wise to settle BROADCAST ENGINEER for only the finest professional stereo turntable and tape equip- ALTEC'S COMPLETE LINE OF ment. It is better to have the STUDIO Pt.\YRP.C1: AND SPEECH - minimum requirements of excellent equipment than a control room INPUT EQUIPMENT IN ONE HANDY crowded with "make do" items. REFERENCE CATALOG. Stereo consoles are available with a wide range of prices and facilities. Some offer stereo channels only for There's no longer any need to search record and tape inputs, while the through hundreds of Altec catalog more complete models even make sheets...everything is now together in provision for stereo network and one "book" especially prepared for the recording and broadcast engineer. In it, remote circuits. Much of today's you will find complete information on... programming is on records and SPEAKER SYSTEMS to satisfy most tapes, but regional "off -the -air re- stringent requirements of studio VU't- lay" stereo networks are springing Cr stom -built Altec control console in ABC -TV's %kcw. Indispensable for accurate A -B Studio One, New York. (lote jack panel contain. comparison of the taped recording with up. Stereo microphone facilities are ing 720 connections that permit virtually any the live rendition for judging accuracy pitching configuration. a must if you want your locally pro- and realism. duced commercials to sound as im- MICROPHONES including the only pressive as your stereophonic music. American -made condensers; 8 new Current models of FM transmit- models of studio dynamics featuring exclusive Altec Sintered Bronze Filters ters are highly efficient, trouble (some models come with individual, free, and easily remote controlled. certified calibration curves); famous All FM transmitters follow one pat - studio stand -bys, the W.E.-type 639 and 633; plus complete information on the tern-a basic exciter and a number revolutionary new 690A dynamic micro. of amplifier stages to produce the phone / transistorized amplifier that di. rectly replaces the carbon transmitter in required power output. The power ordinary handsets to provide broadcast amplifiers in the various models are quality in TV and radio programming. somewhat similar, except in high Banks of Altec 1288 Amplifiers used for AMPS AND PREAMPS you've used or power transmitters (20 kw and up). monitoring by Universal Recording Corp., heard about, including a few that may A wide variety of FM exciters Chicago. be new to you. Covered are power, pro- is gram, compressor, remote mixer ampli- and stereo generators offered, and fiers; preamplifiers; the all- purpose 250 this is one arca in which confusion SU Stereo Control Console. might occur. (Again, it should be TUNERS guaranteed to meet the pointed out that all these units are most critical FCC broadcast standards. subject to FCC type acceptance.) The 314A FM MPX Tuner for the ulti- mate in multiplex network relay ...and A typical exciter and stereo /SCA for off. the -air executive stereo monitor- generating system is shown in Fig. ing, record and tape Pt.kleko:.. the 708A 5. The block diagram explains the "Astro," the only AM /FM MPX Tuner- Amplifier with transistorized power signal path and function of the var- output stages. ious circuits. Coitrolroom view of trree A -7 Systems used If you insist on the best in professional for channel 3- et.kYekcw monitoring at United Plk\VAU, and speech Recording Studios, Holl'wood. -input equipment, Conclusion this new catalog is a MUST. Write to Dept. BE -12 for your FREE copy now, while The selection, installation, and a sufficient supply is still available. operation of FM multiplex stereo equipment requires the careful at- tention of a highly skilled techni- cian. Installation, adjustment, and ALTEE maintenance should be in exact ac- LANSING CORPORATION cordance with the manufacturer's instruction book. Following these ALTEC LANSING instructions, the broadcast engineer can feel confident in planning a Monitoring with Altec 'Duplex "'' Speakers in CORPORATION Capitol's control room. More than 70 cf these 'V Subsidiary of stereo installation that will be a speakers are used throcghout Capitol's record - f7-717 ingTemco- VOUghI, Inc. pleasure to operate and a source of ing studios in Hollywood. ANAHEIM, CALIFORNIA pride and profit.

Circle Item 12 on Tech Dota Card December, 1963 35

www.americanradiohistory.com 66. OHIO SEMICONDUCTORS -Data sheet gives characteristics ENGINEERS' TECH DATA SECTION and applications for line of thermo -electric devices. 67. QUAM -NICHOLS - Catalog lists speakers for PA, back- ground music, intercom, mobile and outdoor applications, high-fidelity, and general replacement. 68. TERADO -Bulletin presents miniature relay used in tele- AUDIO & RECORDING EQUIPMENT vision cameras and other broadcast applications. 52. BROADCAST ELECTRONICS -- Packet contains specs and 69. TUNG-SOL--Base diagram book, interchangeability guide prices for tape cartridge system. (industrial), and subminiature catalog provide tube infor- 53. CROWN- Magnetic tape recorders and players for profes- mation. sional applications are covered in brochure. 70. WALDOM- Buying guide lists electronic and electrical 54. 3M- Bulletin "Sound Talk" carries items of interest to engi- items including solderless terminals, connectors, hardware neers and operators concerned with professional quality and tube sockets. audio recording and playback. 71. WALLACH & ASSOCIATES -Six -page brochure covers cab- 55. NEWCOMB- Brochure covers line of complete public ad- inets for storage and filing of records. tapes, and filmstrips. dress systems. 56. RCA -Data sheet gives physical and magnetic properties POWER DEVICES of magnetic recording tape. 72. CATERPILLAR - Four illustrated booklets describe line of 57. REEVES SOUNDCRAFT - Professional products brochure, natural gas and diesel engine-generators for prime, stand- cross reference chart, and triple -play tape literature give by, and emergency electricity. information on magnetic tape. 58. SAXITONE -Catalog covering tape and audio components RADIO & CONTROL ROOM EQUIPMENT list full selection of items. 59. SPARTA -Spec sheet on 'Tidelipac" tape cartridge service 73. ALTEC LANSING -Brochures cover lines of audio equip- lists tape lengths and prices for both new units and re- ment and speech -input devices for recording and broadcast loading. studios. 60. TURNER - Spec sheet covers 50 /200 -ohm lavalier micro- 74. GOTHAM -Spec sheet gives particulars on steel -plate rever- phone giving properties and applications. beration units available in mono, stereo, and remote control models. 75. LANGEVIN -Catalog shows full line of audio components COMPONENTS & MATERIALS and equipment for professional recording and broadcasting applications. 61. BRADY -Catalog lists line of self -sticking labels and mark- 76. McMARTIN -Catalog describes transistorized amplifiers for ers for wires, cables, and components. cueing, monitoring, talkback, and utility applications. 62. CALVERT - Brochure covers improved vacuum variable for in RF circuits. capacitors use high -voltage STUDIO & CAMERA EQUIPMENT 63. FOUR JAY -Brochure lists features and applications for "Twin -lock" terminals and nylon connectors. 77. BLONDER TONGUE -Product brochure describes transistor- 64. E. F. JOHNSON -Two catalogs cover electronic components, ized vidicon camera with 8" viewfinder screen. and heavy -duty RF components. 78. TELEVISION ZOOMAR- Pocket guide for field coverage of 65. KURMAN-Microminiature relays with high reliability, and all image orthicon lenses gives scene size at distances shock /vibration resistance are detailed in bulletin. from 3 to 1.000 feet.

NEW BRIDGE SIMPLIFIES RF IMPEDANCE MATCHING

FROM TRANSMITTER COMMON POINT OR SIGNAL GENERATOR ARE YOU tatil SURE OF YOUR TAPE SPEED? DELTA MODEL 016.1 Now you can replace OPERATING IMPEDANCE BRIDGE your worn stabilizer with a new Lang Stabilizer Strobe and see at a glance Connect in antenna lead, transmission line, com- if your tape speed is accurate. New Lang Stabilizer Strobe gives you constant 71/2 and 15 i.p.s. speed (5 kw max.), adjust mon point, etc., turn on power reading. Also the new Lang Stabilizer Strobe is for null on meter and read R and X. Insertion machined to within .0002 inches and contributes does not upset directional parameters. Operating to low flutter specifications. Guaranteed constant reading impedance is thus measured. In use by leading and accurate of tapes on all Ampex 300/350 series tape recorders. Used by thousands consultants and station engineers. ($475.00) of Ampex owners throughout the world. 10-day free trial. Only $21.00 with your used stabilizer ELECTRONICS DELTA Order direct from

DELTA ELECTRONICS, INC. ELECTRONICS INC. 4206 Wheeler Avenue, Alexandria, Virginia LANG 507 FIFTH AVE., N. Y.17

Circle Item 24 on Tech Data Cord Circle Item 31 on Tech Dota Cord BROADCAST ENGINEERING 36

www.americanradiohistory.com 79. WARD LEONARD -Solid -slate lighting control system for small theatres, schools, TV studios, and similar facilities BOOK REVIEWS are described in product bulletin.

TELEVISION EQUIPMENT Analysis, Transmission, and Filtering of Signals; Man - 80. INTERNATIONAL NUCLEAR-Line of transistorized video equipment is described in catalog. sour Javid and Egon Brenner; McGraw -Hill Book Co., 81. JERROLD -Short form catalogs cover three lines: TV /FM Inc.; 462 pages, $12.75. This book presents, in unified distribution systems equipment, Paralog antennas, and Super Powermate amplifiers. form, clear treatment of a variety of subjects including 82. RAYTHEON -Data sheet discusses damper amplifier for frequency analysis, an introduction to modulation microwave radio or cable circuits handling monochrome or color television signals. theory, and an introduction to noise calculations. The 83. RIKER- Set of brochures present all- transistor video modules necessary mathematics are developed as needed and which may be assembled, changed, or expanded at any time. examples are presented which demonstrate the applica- tion of these concepts to problems involving distributed TEST EQUIPMENT & INSTRUMENTS parameter systems. The problem of wave propagation 84. SPRAGUE -Circular fully describes features and applica- tions of interference locator for determining sources of radio along a transmission line is treated both in transient and and television interference. steady state forms, to demonstrate the application of TOOLS the developed analysis methods. The system theory 85. HUNTER INDUSTRIES - Brochure and booklet list special concept serves as an underlying goal of the develop- tools for electronic components assembly, and describe serv- ment. In this framework the serve as ices of special products dept. examples treated models for general systems, rather than simple demon- TRANSMITTER & ANTENNA DEVICES stration of the developed techniques. Analysis is treated 86. BAUER Brochure describes "Log Alarm" system for auto- matic transmitter logging and monitoring. as a fundamental tool of engineering. Consequently, 87. CO. EL. -Spec booklets cover broadband dipole TV an- the approach avoids merely generating a collection of tennas for VHF and UHF, multiguide UHF slot antennas. problems and their solutions by presenting them as directional antennas for 1 -kw UHF transmitters, wide band FM antennas. VHF and UHF notch diplexers. and filter - required to develop the subject. Numerous problems of plexers. varying difficulty are presented as well as 88. G.E.L. -Data sheet describes local automatic transmitter examples, logging equipment which makes use of a single chart proofs, and practical system analysis. This book is recorder. recommended for the book shelf of the engineer who 89. JAMPRO -Spec sheets provide details on dual -polarized FM antennas. is familiar with normal engineering mathematics.

The new Electro -Voice Model 654A can replace up to three of your 3 -WAY present microphones... and do a better job to boot! It's the ideal size for hand -held use -and. the Cannon MICROPHONE XLR connector ends your cable problems. It's also an easy- wearing lavalier, with wide range and plenty of output. And on a floor or desk stand the 654A is the finest all- purpose microphone you can buy for voice or music. The lanyard and slide -clamp mounting supplied are easy to use and versatile, too. The 654A will give broadcast fidelity for years! Un- conditionally guaranteed for two years, except for finish -guaranteed for life against defects in materials or workmanship. The 654A is omni -directional, with E -V's tough Acoustalloye dynamic diaphragm that will take the hardest accidental abuse, yet still deliver peak -free natural response. New Acoustifoam® filter gives added freedom from "pops" and better reliability than any other filter - regardless of type. New epoxy finish is chip -proof for longer -lasting beauty.

In the studio, or out on remotes, with the E -V 654A handy... you'll do more jobs- better -more dependably than ever before. Write for complete technical specifications plus name of your nearest franchised E -V distributor, today!

Model 654,4 includes stand adapter and neck _7f ' lanyard. List price $100.00. ELECTRO- VOICE, INC., Commercial Products Division, Dept. 1231V, Buchanan, Michigan gkere7iilic Subscribe today to "Microphone Facts ", fact -filled, free serles on modern microphone techniques. Request on studio letterhead.

Circle Item 25 on Tech Data Card December. 1963 37

www.americanradiohistory.com manufacturers unless the equipment Is Professional Services used and no longer owned by the manu- Advertisers' Index IS a> I= MN facturer. Display advertising must be ! ! ! t t ! purchased in such cases. Altec Lansing Corp. 35 VIR N. JAMES EQUIPMENT FOR SALE American Concertone 21 CONSULTING RADIO ENGINEERS Ampex Corp. 15 Applications and Field Engineering Commercial Crystals and new or replace- 345 Colorado Blvd. ment crystals W. E., Phone: (Area Code 303) 333 -5562 for RCA, Gates, Bauer Electronics Corp. 30 Bliley and T -IC holders; regrinding, re- Belden Mfg. Co. 3 DENVER 22, COLORADO pair, etc. BC -604 crystals. Also A. M. monitor service. Nationwide unsolicited Broadcast Electronics 6 30, 32, 38 Member AFCCE testimonials praise our products and fast service. Eidson Electronic Company. Box 96. Temple. Texas. 9 -61 tf CBS Labs, Inc. 5 Continental Electronics 32 SYNCHRONOUS MAGNETIC FILM Crown International 4 RECORDER /REPRODUCER PROMPTING EQUIPMENT. Used one. MAGNETIC TAPE RECORDERS two Full NEW -THE portable MINITAPE syn and three prompter packages. Delta Electronics, Inc. 36 chronous 13 ib., battery operated one year warranty. Limited quantity. magnetic tape recorder for field re. TELESCRIPT CSP, Inc., 155 W. 72nd. St., Dymo Industries 26 cording. New York 23. New York. 10-63 2t THE STANCIL- HOFFMAN CORP. Eastman Kodak Co. 7 845 N. Highland, Hollywood 38, Calif Dept. B HO 4 -7461 REAR SCREEN PROJECTORS. Used No. Electro-Voice, Inc. 37 7000 3! x4" R.S.P., 70 slide capacity, !á Electronics, Missiles & sec. fast slide changer, remote control. Taken in trade on new Dual Head R.S.P. Communications, Inc. 28 JOHN H. BATTISON & ASSOCIATES Full one year warranty. Limited quan- tity. TELESCRIPT CSP, Inc., 155 W. 72nd. Fairchild Recording CONSULTING RADIO ENGINEERS New York 23. New York. 10 2t TV -AM -FM & Microwave Applications and St., -63 Equipment Corp. 27 Installations Specializing in all forms of communications engineering. GOVERNMENT SURPLUS, NEW 10 CM. Gates Radio Co. Cover 2 422 Washington Bldg. Washington 5, 0. C. WEATHER RADAR SYSTEM-Raytheon, Gotham Audio Corp. 31 275 KW peak output S band. Rotating Phone ST 3 -3484 yoke P.P.I. Weather Band 4, 20 and 80 Established 954 mi. range. Price $975 complete. Has Hunter Engineering 28 picked up clouds at 50 mi. Wt. 488 lbs. Radio Research Inst. Co., 550 5th Ave.. International Nuclear 23 New York, New York. 8 -63 6t Corp. Classified Lang Electronics, Inc. 34, 36 MICROWAVE ANTENNAS. Parabolic, 6 Magnecord Div., Midwestern foot dia., Andrews, Spun Aluminum. 1700- Advertising rates in the Classified Sec- 2400 MCs Complete with mounting Instruments 29 tion are ten cents per word. Minimum bracket, Di -pole, de- acres. etc. Unused - McMartin Industries Cover 3 charge is 82.00. Blind box number is 50 Crated - Cheap. One Hundred Available Moseley Associates 32 cents extra. Check or money order must Sierra -Western Electric 1401 Middle Har- be enclosed with ad. bor Road, Oakland, Calif. Tele. 832 -3427. The classified columns are not open to 10 -62 2t RCA Broadcast and the advertising of any broadcast equip- ment or supplies regularly produced by Television Equipment 33 Ampex Head Assemblies for 300 and 400 RCA Electronic Components series recorders reconditioned. Service and Devices Cover 4 includes lapping and polishing all three Russco Electronics Mfg. 34 head stacks, cleaning entire assembly, readjusting and replacement of guides. and realignment of stacks as to azimuth Sarkes Tarzian, Inc.. SPOTMASTER and zenith. Full track assemblies- $60.00. Semiconductor Div. 19 Taber Manufacturing & Engineering Co., 2619 Lincoln Ave., Alameda, California. Saxitone Tape Sales 38 8 -63 5t Scala Radio Co. 32

Telemet Corp. 17 Western Electric 40581 5 Kilowatt AM transmitter. Condition perfect. Make Telescript, Inc. 24 offer. Write Broadcast Engineering, Dept. 105. 12 -63 -1t

ENGINEER. Advisory capacity, must know thoroughly all phases of storecast 4 -TRACK STEREO TAPES: receivers, design, alignment and most of If saving of time and money are important- you'll all their installation. Can be presently find a full and complete stock of recorded tape at employed, should have test equipment O WITH for same. Write P. O. Box 6731. Cleve- land, Ohio. 12 -63 -2t ó F MONEY -BACK 30 60% F GUARANTEE LANGEVIN AMPLIFIERS available in SAXITONE RECORDING 'TAPES EQUALIZED TURNTABLE excellent condition with tubes, trays and 275' Plastic, 3" Reel .35 plugs. 13 AM -5115 pre -amplifiers @ 600' acetate (plastic), 5" reel .75 PREAMPLIFIER $38.75, 4 AM -5117 program ampliifers @ 600' MYLAR 5" reel .85 $45.15, 1 PS -5206 power supply @ $70.60. 900' MYLAR (polyester) 5" reel .89 The Model TT -20A is a compact, low dis- Hugh T. McKenny, R.F.D. No. 1, Milton, 1200' MYLAR, 1h-mil.. 5" reel 1.18 tortion, transistorized turntable preamp for Vermont. 12 -63 It 1200' MYLAR, tensilized, 5" reel 1.59 VR cartridges, with built -in NAB equaliza- 1200' acetate (plastic) 7" reel 1.15 tion. Design ingenuity reduces residual 1200' MYLAR, t ya -mil. (strong) 7" reel 1.29 noise level to better than 65 db below rated TRANSMITTING TUBES FOR SALE - 1800' acetate (plastic) 7" reel 1.39 1800' output. Small requirements Immediate Delivery on 6076 Power Tet- MYLAR, 1 -mil. thick, 7" reel 1.89 current permit $170, 2400' MYLAR, untensilized, 7" reel 2.59 6 volt dry cell battery operation, eliminat- rodes, at $235 each. 3X2500F3 - 450TL -S35, 4 -125A -$22.50. 872A- $5.25. 2400' MYLAR, tensilized, 7" reel 2.89 ing AC hum worries. Response, 30- 16,000 575A- $15.50. Also SPECIAL HIGH cps ± 2 db ... output -12 dbm, 600 ohm QUALITY ENGLISH ELECTRIC 6166- emitter follower ... distortion under 1% at $840. All tubes are factory new, 1000 double rated output size, 2yS x 2342 hour warranty, from the largest whole- WOLLENSAK ... TAPE RECORDERS x 5y¢'. Priced from $46.50; transformer sale supplier of broadcast tubes. Inquire output and power supply available. Also about our special quotes for complete Educational spare tube kits. CALVERT ELECTRON- ECTIO Discounts start from S1 available as a flat amplifier Model BA -20A. ICS, INC., Dept. BE -12. 220 E. 23rd St., 04 Write or wire for complete details. s New York 10, N. Y. (212) OR 9 -1340. t WOLLENSAK delivers a bigger wallop than many recorders twice its size. We have the STEREO MICROPHONES - Matched most complete selection! BROADCAST ELECTRONICS, INC. pair of Electro-Voice Model 623 Slim 1776 Columbia Rd. 5300 Brookville Road Dynamic microphones, unused, in origi- Northwest, Wash., D.C. Silver Spring, Maryland nal packaging. Price, complete, $50.00. FREE 50 -PAGE Write BROADCAST ENGINEERING, CATALOG NO. B -1 Circle Item 26 on Tech Data Card Dept. 106. Circle Item 27 on Tech Data Card

38 BROADCAST ENGINEERING

www.americanradiohistory.com No other FM MONITORS can do so much!

FM 'SCA MULTIPLEX MONITOR FCC TYPE APPROVED -3 -116 This is the most versatile instrument available for monitoring all main channel modulation and SCA Multiplex operating characteristics. Com- patible with FM stereo. Direct meter readings of: Total Modulation Crosstalk SCA Modulation SCA Injection SCA Frequencies McMartin TBM -4000

McMartin FREQUENCY & MODULATION MONITORS TBM -3000 FCC TYPE APPROVED =3 -113, -3 -119 The TBM -3000 is a completely self -contained frequency monitor and the TBM -3500 is a self- contained modulation monitor.

The 3000 used in conjunction with either the 3500 or 4000 fulfills

the FCC requirement for a station monitor.

McMartin The TBM -3500 is completely compatible with FM stereo. TBM -3500

RF AMPLIFIER FOR REMOTE MONITOR OPERATION The TBM -2500 will drive any combination of two monitors including other brands. Isolated high and low level outputs. McMartin TBM -2500 Excellent stability and long tube life. 2 watt output with 1000g v input. Complete with yagi antenna and coaxial cable.

Originality by McMartin Industries, Inc. 605 North 13th Street Omaha. Nebraska Code 402 - 342 -2753 In Canada Sold By: Canadian Marconi Company, Montreal 16, P. Q.

'Mk Or Circle Item 28 on Tech Data Card

www.americanradiohistory.com New RCA -5820A Partial Adjustment Curve -Extension of the RCA -5820A warranty period from 500 to 750 hours' service provides more generous coverage.

i00

90

80

70 .4371.0 Io,e.rg.l:0./J . ,

60 k WARRANTY

50 ADJUSTMENT TERMS

1. Adjustment will be limited :c claims 40 which are presented promptly after tube is found to be defective.

30 2. All tubes claimed to be defective will be subject to inspection and test by RCA_

3. Tubes returned to RCA will be consid- 20 ered for adjustment only if return was authorized by RCA and made in accord- ance with instructicns issued by RCA. lo 4. RCA will be responsible for transpor- tation costs on returned shipments pro- vided adjustment is subsequently al- 0 lowed. RCA, however, cannot accept 100 200 300 400 500 600 700 750 charges for packing, inspection, orlabo- Hours Of Service costs in connection Nith tubes returned for inspection or adjustment.

5. In all cases, RCA reserves the righ: to make adjustment by repair, replace- ment, or credit. Where full adjustment is allowable, adjustment norma ly will be made by replacement in kind but RCA NEW! reserves the right to limit the adjust- ment period on the replacemen: tube to the unexpired portion of the original tube warranty. Where partial adjustmen: is allowable, adjustment will normally 50% LONGER WARRANTY: be made by the issuance of credit. 6. Adjustment credits will be based or prices in effect on date of claim for ad- justment.

7. Replacements for tubes found subject to adjustment will be shipped F.O.B. citl COVERAGE of destination with transportatior charges prepaid by RCA to city of desti- nation. for the popular RCA-5820A image orthicon 8. Adjustment will not be allowed for tubes which have been subjected to RCA now gives further assurance of reliability and economy abuse, improper installation or applica- by RCA tion, alteration, accident or negligence extending the warranty period on the -5820A from in use, storage, trarsportation, or han- 500 to 750 hours of service. Hours of service are total hours dling nor for tubes on which origina identification markirgs have been re- of operation, including time that power is applied to filament moved, defaced, or falsified. or heater. 9. Final determination as to where an RCA electron tubes are manufactured to high quality adjustment is allowable rests will RCA. standards and are warranted against defects in workman- 10. No warranties or obligations on the part of RCA Electronic Components anc ship, materials and construction. If a defect is of a latent Devices, other than the aforemertioned nature, it normally will reveal itself shortly after the tube is are to be implied with respect to elec- tron tubes, and RCA cannot be respon- placed into service and RCA will allow adjustment for the sible for labor or ary other charges it RCA- 5820A, subject to the terms set forth herein, in accord- connection with the failure or replace- ment of electron tubes. ance with the following: Users should present claims for adjust- Full adjustment is allowed for tubes failing within 50 ment to their RCA special market dis- tributor except that a claim for a tube hours of service. Partial adjustment up to 750 hours of which had an advance Return Aithoriza- service is allowed in accordance with the Adjustment tion packaged with the tube is to be handled in accordance with inrrjctions Policy Table which is shown graphically above. Adjust- on the authorization ments are limited to claims presented within 11/2 years after the tube was shipped by RCA Electronic Compo- nents and Devices. ßYIlY4YIlri4 R7&11,12 lYt6ßt7 g71/I4tfi RCA ELECTRONIC COMPONENTS AND DEVICES, HARRISON, N.J. AVAILABLE THROUGH YOUR AUTHORIZED DISTRIBUTOR The Most Trusted Name in Electronics OF RCA BROADCAST TUBES

www.americanradiohistory.com