A HOWARD W. SAMS PUBLICATION DECEMBER 1962 75c
FEATURING Mobile Videotape Installation-TWW, England 10 Preventive Maintenance for the Studio 12 Installing Directional Antenna Systems 14 Camera Tube Alignment Using 30 Cycles 26 1962 Subjject Reference Index 32 Broadcast Engineering the technical journal of the broadcast -communications industry
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www.americanradiohistory.com the technical journal of the broadcast -communications industry Broadcast Engineering
Volume 4, No. 12 DECEMBER, 1962
CONTENTS FEATURES Mobile Videotape Installation-TWW, England 10 Preventive Maintenance for the Studio 12
THE S--Lyt-li Installing Directional Antenna Systems (Part I) I4 AUDIO ANNOUNCER Planning a New FM Stereo Station (Part II) 22 tarts on cue, Camera Tube Alignment Using 30 Cycles 26 Stoss when thru- 1962 Subject Reference Index 32 or-lati i ous'j DEPARTMENTS oK ttxu ,
Let the Audio Announcer be your Letters to the Editor 6 endless magnetic tape loop voice. its rugged, modular construction Technical Talks 16 allows precise voice or signal playback continuously or "on call" as required. About the Cover 28 The Audio Announcer plays the Cousino-patented Echo-Matic car- Engineer's Exchange 30 tridge which provides automatic threading and rewinding of the 37 closed loop magnetic tape. News of the Industry Other models to record and play- back voice and inaudible "beep" New Products 39 trigger tones are available. Or consider the Cousino tape play- 42 ing mechanism for installation Classified Ads into your electronics assembly. Professional Services 42 Fully transistorized- no warm- up or standby power required; Automatic shutoff - with me- "... 1111:....:. tallic foil or silver paint; PUBLISHER: Howard W. Sams GENERAL MANAGER: Mal Parks, Jr. Entirely portable- weighs only EDITORIAL: Executive Editor, Verne M. Ray; Editor, Forest H. Belt; Managing Editor, Stuart Soll; 9 lbs. Consulting Editor, John H. Battison. CIRCULATION: Manager, Pat Tidd; Assistants, Katherine Smith; LaVon Willard. from PRODUCTION: Manager, Robert N. Rippy. ADVERTISING: Sales Manager, John W. Grace; EAST: Charles Horner, Howard W. Sams & Co., York, N. Y., Phone-MU 8-6350; MIDWEST-Hugh Wallace, Howard 99.7J Inc., 3 West 57th Street, New Write today giving details of your 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, requirements . . . to the CALIF., Maurice A. Kimball Co., Inc., 2550 Beverly Blvd., Phone-DU-8-6178; SAN FRANCISCO, "TAPE LOOP PIONEERS" Maurice A. Kimball Co., Inc., 580 Market Street, Phone-EX 2-3365; PARIS 5, FRANCE, John Ash - John 12 Bear craft, 9 Rue Lagrange, Phone-ODeon 20-87; LONDON W.C. 2, ENGLAND, Ashcraft, Street, Leicester Square, Phone-WHitehall 0525; TOKYO, JAPAN, International Media Representa- tives, Ltd., Kisha Kurabu 14, 2 -chame Marunouchi, Phone-(502) 0656. 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. of BROADCAST ENGINEERING is published monthly by Technical Publications, Inc., an affiliate ELECTRONICS Howard W. Sams & Company, Inc. Editorial, Circulation, and Advertising headquarters: 4300 CORPORATION West 62nd Street, Indianapolis 6, Ind. 1 9 4 1 FRANKLIN AVENUE TOLEDO 2, OHIO A HOWARD W. SAMS PUBLICATION BPA
BROADCAST ENGINEERING 4
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December, 1962 5
www.americanradiohistory.com LETTERS to the editor ------DEAR EDITOR: I understand that Harold Ennes has written a book on TV systems mainte- nance. I will appreciate it if you can tell me the name of the publisher, the title of the book, and the price. OVER 1400 SIZES AND TYPES OF IERC HEAT- C. G. ADAIR DISSIPATING ELECTRON TUBE SHIELDS San Antonio, Texas For the benefit of the hundreds who have written, Harold Ennes is currently authoring a 10 -volume "Broadcast Engi- neering Notebooks" series for Howard W. Sams & Co., Inc. The first volume, "Television Tape Fundamentals," is to be published this month, and is priced at $5.95. Several volumes are planned for TV systems maintenance, later in the series.-Ed.
DEAR EDITOR: If possible I would like to obtain a reprint of your series, "Audio Studio Maintenance" and "Radio Transmitter ARE EFFECTIVELY COOLING MILLIONS OF Maintenance." HARRY A. ETKIN TUBES, EXTENDING LIFE AND RELIABILITY, Levittown, Pa. Sorry, individual reprints of the arti- cles are not available, but we still have most of the back issues, which are avail- able for just 750 each. If you can hold off just a bit longer, however, you can obtain a booklet containing all the main- tenance series articles with a new or renewal subscription order.-Ed.
DEAR EDITOR: I enjoyed reading my article on the WINC Satellite in the October issue. However, I have been besieged with calls AND MAINTENANCE and letters regarding errors in the circuit REDUCING DOWN -TIME diagrams. COSTS IN THOUSANDS OF MILITARY AND On page 30, the battery designations are inaccurate. The top terminal which reads +18 V should, of course, read - 18V, and the terminal below it should read -6V. In the pickup preamplifiers, the coupling capacitors should be 2 in- stead of 200 mfd, and the base resistors should be 82K instead of 8200. The re- sistors shown in the pad on the limiting amplifier diagram on page 32 should be 47 instead of 47K. The negative 18 volts goes only to the program amplifier; all voltages in the preamplifiers should be -6 instead of -18. PHIL WHITNEY INDUSTRIAL ELECTRONIC EQUIPMENTS! WINC Winchester, Va. tie. 11/.1e today for ¡he facts or sovw yoe can improve equipment Yipes! Spots on our collective wild Phil. We reliability with IERC Keet-L1issivating Tube shields. Sorry for the schematic, held a kangaroo court recently to pre- vent further such occurrences. Note to readers: Mr. Whitney has also provided IERC us with improvements on his original circuit; the bypass capacitor at the -6 lnternrional Electronic Research Corporation volt tap in the battery divider should be 500 mfd at 25 volts, and the 2N109 Bouleve r 1, Burbank, California 135 West Magnolia input coupling capacitor should be 10 ;Fc +-nn Manufir,' revs. Europele:, Paris, fra ice. G2rNrd Mig & Eng. Co.. Ltd. Swindon, England mfd at 15 volts.-Ed.
BROADCAST ENGINEERING 6
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December. 1962 7
www.americanradiohistory.com Frank Marx (R), Pres., ABC Engineers, and Charles Colledge, V.P., RCA Broadcast and Communications Division, load up one of ABC's new total solid-state TR -22's.
www.americanradiohistory.com New All -Transistor RCA TV Tape Recorder A "new generation" is on its way! Dozens of these fully - TV, Reno, Nevada; to WEAT-TV, West Palm Beach, transistorized console -model TV tape recorders are Florida . . and so it goes! coming off production lines in Camden, going to U.S.,. Shipments of these compact, solid-state recorders are Canadian, and European users ... NOW!' scheduled well into next year. Camden facilities have The first of these striking new -generation units went to been stepped up to a two -shift basis to fill commercial Washington-two for ABC's new facility there, and one and military orders as fast as possible. Order now! for the Navy's Photographic Labs. The fourth and fifth See your RCA Broadcast Representative. Or write air -jetted to England and France; then units to CFPL RCA Broadcast & Television Equipment, Dept. P-367, in Canada; to WBRE-TV in Wilkes-Barre; to KCRL- Building 15-5, Camden, New Jersey.
The Most Trusted Name in Television
www.americanradiohistory.com MOBILE VIDEOTAPE by Jack Alexander*-Local conditions demand compact designs for overseas mobile units. The remote videotape INSTALLATION truck described in this article suggests application of similar low-cost remote trucks in the United States. -TWW, ENGLAND
The remote unit shown in Fig. I was built by Rank Cintel of London for use on the narrow roads of England and other European coun- tries. Although small, it provides the facilities required to cope with production and operational emer- gencies. Because of the various television standards in Europe -405, 525 (for use with U.S. equipment) 625, and 819 lines-an Ampex Inter - switch system was incorporated to provide instantaneous selection of line standards. Alternate provisions were also made for primary power; one is an autotransformer installed to supply 117 volts from the com- mercial power line. Should there be no primary source available, a small Fig. 1. The complete TWW remote videotape truck. gasoline or diesel generator, towed Most television remote trucks in the mobile units are smaller. A good in a trailer from the hitch at the United States are quite large, while example is a videotape unit built for rear of the truck provides the nec- in countries such as England, where one of the British commercial op- essary power. a smaller scale is the general rule, erations, TWW, which provides in- teresting material for consideration Design Considerations 'TV Consultant, Washington, D. C. by U. S. television engineers. Nine criteria were considered in designing the vehicle. These were: 1. Adequate working space. 2. Ample storage facilities for equipment and spares. 3. Elimination of mechanical vi- bration. 4. Comfortable interior for a relaxed working atmosphere. 5. General ease of operation and setup. 6. Location of individual units for quick maintenance and accessibility. 7. Maximum use of available space. 8. Air conditioning 9. Heating. For optimum use of the available space, the equipment is mounted on frameworks, 3" Fig. 2. Interior of truck showing the special Cintel frames during construction. specially designed
i0 BROADCAST ENGINEERING
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Fig. 3. Floor layout of the TWW mobile unit. Fig. 4. Layout at the forward end. high by 15" deep by 52" wide. The switching panel mounted on a stand- high. The floor is flat with no wheel electronics equipment is affixed to ard 19" rack and centered. Also or transmission "humps," and frames which can be swung out for located on this central panel are the through careful selection of colors service. These structures, two on power control panel and clock. A and decor, any tendency toward one side of the van, and one on the mechanical clock is employed to claustrophobia is avoided. Cables other, can be seen in Fig. 2. eliminate timing errors due to power are routed through floor ducts which supply problems. are large enough to permit future Power Sources All of the units normally housed alterations. All operating cables are A hinged panel on the right side in 7' racks are mounted on double stored in enclosed trunks (which are of the truck swings up to reveal the swinging frames along the left side accessible from the outside) and are primary power -input cubicle. A of the interior (Fig. 5). The top of connected through a panel behind a regulator supplies stabilized power this special rack is covered with hinged door. with a nominal voltage of 240 volts Formica to provide a large work The special Dennis Heron chassis to all the utility outlets in the truck. space. The bulk tape eraser and which carries the truck body can A secondary stabilized line feeds splicer are stored in a single frame be supplied with a gasoline or diesel the autotransformer beneath the along the right side of the truck engine to power the complete unit. floor at the rear of the truck. From (Fig. 6). The cabinet section of this Considerably smaller than most re- this transformer, 117 volts is dis- assembly provides for tape, head, mote trucks made in the United tributed to outlets on the mainte- and material storage. States, this mobile videotape unit is nance and service benches, and Although the truck may be small capable of equal performance qual- directly to the recorder racks. by U.S. standards, the interior ity under a variety of rigorous con- The interior lighting can be pow- measures 17' long by 7' wide by 7' ditions. ered by either of two systems-the emergency generator, which oper- ates from the truck batteries, and the standard 240 -volt system. A number of ventilating fans for the work space are also fed from the standard power line. Skylights, win- dows, and inlet ducts provide ade- quate ventilation under most weath- er conditions. However, air-condi- tioning and heating units can also be provided if extreme weather con- ] 7 ] 7 ditions preva i I Fig. 5. Equipment layout on left side. Physical Layout The floor layout of the mobile unit is shown in Fig. 3. The Ampex video tape recorder is fitted across the front end of the truck (Fig. 4), more or less centered for maximum stability, freedom from roll, and best weight distribution. The con- sole can be swung forward for main- tenance after the floor -mounting PP INPUT PPP... bolts are removed. One 17" Cintel monitor is posi- nn tioned at each side of the console with the waveform monitor and Fig. 6. Equipment layout on right side.
December, 1962
www.americanradiohistory.com PREVENTIVE by Jack Walsh - A schedule you MAINTENANCE can use as a guide for planning your own efficient and practical preventive FOR THE STUDIO maintenance plans.
Asterisk (*) denotes monthly maintenance. One drop of oil Date Preventive maintenance is a neces- in all cases. Tube checks are bi -weekly. Initial as Console sity in all broadcast operations, Clean dust from inside of console. anyone responsible for equipment Replace bulbs if necessary. operation knows. Attention to a Use toothbrush and carbon tet to clean all pots and switches. regular maintenance schedule Check tubes in the following: From left to right: should not be taken lightly, nor can Preamp No. I V201 5979 enough be said concerning its im- V202 5879 portance. The simple procedures in- Preamp No. 2 V201 5879 V202 5879 volved can often eliminate a prob- Preamp No. 3 V201 5879 lem before it becomes serious, thus V202 5879 preventing a costly loss of air time. Preamp No. 4 V201 5879 V202 5879 There are too many separate Preamp No. 5 V201 5879 steps in preventive maintenance to V202 5879 them all. It is therefore Preamp No. 6 V201 5879 memorize V202 5879 a good idea to formulate a regular Booster Amp V201 5879 schedule which includes the small- V202 5879 they Booster Amp V201 5879 est details (Fig. 1) because V202 5879 may easily be overlooked. Along Program Amp V301 5879 with the regular maintenance items V302 5879 V303 6V6 on the form, space should be pro- V304 6V6 vided for the date, engineer's ini- Limiter Amp V601 6386 tials, and for any new practices V602 6V6 V603 6V6 which may subsequently be adopted. V604 6AL5 The schedule should include lub- Cue amp V801 5879 of motors and other mov- V802 5879 rication Check voltage of power supply (300 VDC) ing parts, voltage checks (generally outlined by the equipment manu- Fig. 1. Portion of control -room schedule listing details of console maintenance. facturers), tube checks, as well as demagnetization and alignment Spotmaster Recorder checks of tape -recorder heads (Fig. Clean heads with Spotmaster cleaning fluid. 2). Other essential items are clean- Clean roller and capstan drive shaft with Spotmaster cleaning fluid. switches and attenuators: Check pressure on capstan pinch roler. See manual. ing of all *Oil sleeve bearings on the drive motor. One hole in each special cleaning instructions for end of the motor shaft. tape guides, pressure rollers, etc.; Check tubes: VI I2AU7 V2 I2AX7A and finally, a complete operational V3 I2AV6 check of all components. V4 I2AX7A For simplification, the schedule Ampex recorder No. 1 (nearest to console) should be arranged in the order Clean heads with head cleaner. maintenance is performed. Our Clean all metal tape guides with carbon tet. Clean capstan with carbon tet. schedule, comprising twelve pages, Clean rubber idler roller with Spotmaster cleaning fluid. is divided into three major sections *Oil the upper sleeve bearing of the capstan drive motor. -Control Room, Production Con- *Oil the capstan drive motor as per manual. Page 5-8. *Oil the capstan idler roller. See manual Page 5-8. trol Room, and News Room. Typi- *Demagnetize heads. See manual. cal items include consoles, turn- *Align heads. See manual. tables (Fig. 3), tape recorders, and Check tubes: IVI 12AX7 IV2 12AT7 monitor receivers (Fig. 4). 2V3 12AX7 There are five columns to the 2V4 12AX7 right of all steps in the form; each 2V5 12AU7 IV6 I2AU7 represents a week, and a series of 3V7 6X4 'Chief Engineer, WMAK, Fig. 2. Studio schedule for tape machines. Nashville, Tenn.
12 BROADCAST ENGINEERING
www.americanradiohistory.com twelve pages comprise a month's schedule. Such a form may be ex- panded to cover two, three, or more Date months, according to the need; Initial however, keep in mind the increas- Turntable No. 2 (16") ing problem of filing these schedules Remove platter, clean motor, casting, etc. as they *Cil points as shown in the instruction manual. (IO points) become bulkier! Clean with carbon tet: motor pulley As for details, notice the remind- drive surface of platter ers for actual checking of each tube, Clean the idler wheel with Spotmaster cleaning fluid. *Oil motor. which also serve as a record of tube Check tubes in TT preamp: VI EF86 life. The same plan applies readily V2 EF86 to styli. Since there is a variety V3 I2AU7 V4 6X4 of lubricants and cleaning solvents Replace styli when needed. Date available, the type chosen for each Turntable No. 3 (16") should be indicated (Fig. 5). In some cases there are notes Remove platter, clean motor, casting, etc. *Oil points as shown in the instruction manual. (IO points) which, with practice, become rather Clean with carbon tet: motor pulley nonessential, but continue to serve drive surface of platter Clean the idler wheel with Spotmaster cleaning fluid as a ready reference when needed. *Oil nsator. Examples are notes on power -supply Check tubes in TT preamp: VI EF86 voltages, locations of equipment, V2 EF86 V3 I2AU7 and lubrication references in instruc- V4 6X4 tion manuals. Re?lace styli when needed. Date A simple code is used in marking the columns to denote the operation performed. A check mark indicates Fig. 3. Turntable maintenance schedule. the item was inspected and found in proper order. An R denotes the replacement of a tube, stylus, etc., and an X signifies that the opera- Date tion was was Initial postponed or not Monitor Receiver No. 1 scheduled to be done at that time. Check tubes: VI 6BJ6 The mark O means that repairs were V2 6U8 made and a description of the work V3 6BJ6 V4 6BJ6 performed is noted on the back of VS 6AL5 the form. Thus, there will always be V6 I2AX7 a mark V7 6AK6 beside every item in the V8 6X4 schedule, explaining what has or has not been done. Monitor Receiver No. 2 An asterisk (*) Check tubes: VI 6BJ6 before any item V2 6U8 in the schedule denotes a monthly V3 6BJ6 check or lubrication-otherwise the V4 6BJ6 function V5 6AL5 is performed weekly. A V6 I2AX7 regularly scheduled proof - of - per- V7 6AK6 formance, included with preventive V8 6X4 maintenance, should be run more often than the F.C.C. requires. Such tests of the various components will Fig 4. Schedule for news -room monitor receivers. often indicate troubles which do not ordinarily appear as a result of tube Date and voltage checks. Initial While the specific schedule set up Mognecorder PT6-AH for this station may not serve di- *Oil front and rear of drive motor. *Oil front and rear of rewind motor. rectly for other broadcast stations, *Oil felt washers on the take-up clutch assembly. because of the great many special *Oil felt washers on the rewind clutch assembly. considerations which *Disassemble guide rollers and clean all parts with carbon tet. do not always *Cil the felt wick and reassemble. apply, it can certainly serve as a Clean the capstan with carbon tet. general outline of preventive main- Clean the rubber pressure roller with Spotmaster cleaning fluid. tenance procedures you can use. *Clean and oil the pressure roller shaft. CAUTION: DO NOT USE CARBON TET ON ANY BEARING A Preventive Maintenance Sched- SURFACES. ule can be too brief, and thus defeat *Oil felt wicks on front and rear of the capstan shaft. the purpose any *Clean the rubber covered idlers in rear with Spotmaster cleaning fluid - detail which *Clean the rubber covered drive pucks with Spotmaster cleaning fluid. would help keep the station on the air should be added. Fig. 5. Portion of schedule specifying cleaning and lubrication preparations.
December, 1962 13
www.americanradiohistory.com by John H. Mullaney, Peter V. Gureckis, INSTALLING DIRECTIONAL John R. McKenna* - Valuable pointers for all engineers concerned with ANTENNA SYSTEMS locating antenna systems
Planning a broadcast antenna some question, a civil engineer must quadrant. For example: the bearing system and surveying for the loca- visit the site and accurately mark N -50°-E means the direction 50° tion of towers present several crit- the location. east of the north reference; while ical problems. Improper handling In cases where the services of a the bearing 5-10°-W means the can result in the need for one or civil engineer or surveyor are not direction (rotating clockwise from more towers to be dismantled and employed, the geographic coordi- the north reference) 180° or due moved to a correct location. Not nates of the site are determined south of the north reference, plus only does this cause serious delays from the map and by computation, another 10° of rotation to the west. and financial difficulties for a sta- relying upon the accuracy of the To most radio engineers, the word tion owner, but it might prompt him site -location data furnished by the bearing indicates a True direction to take legal action against the sur- applicant. For the purpose of an (e.g., N -10°-E would indicate 10° veyor or civil engineer who did the application, this method is satis- east of north). work. factory; however, for determining One way to determine if a plat bear- This article is not meant to be a the exact latitude and longitude in is based on True or Magnetic used for complete treatise on the subject of regard to the center -line of an array ings is to note the arrow refers antenna surveying, but rather a and in relation to True North, it is depicting north. A half arrow a full guide for making recommendations not. A surveyor or civil engineer to Magnetic North, whereas North. to the surveyor or civil engineer. must, in this case, recheck geo- arrow refers to True Ordinarily, when a broadcaster graphic coordinates to insure ac- An azimuth, on the other hand, selects an antenna site, his consult- curacy. is a horizontal angle measured merid- ing radio engineer furnishes a Most surveyors do not give bear- clockwise from a reference United States Geological Quad- ings in relation to True North, but ian. Unless the reference meridian sur- rangular Sheet. If this type of map instead use Magnetic North as their is expressed as True North, the bear- is not available for the area under base. Consequently, it is possible to veyor will assume Magnetic consideration, a county or other obtain plats which, if not corrected, ings. on which lines of latitude and will result in incorrect layout of the map Multi -Tower Arrays longitude are indicated should be towers with reference to True North. obtained. The owner marks the site Inasmuch as directional antenna In addition to the normal care on the map if there is no doubt as systems must be precisely laid out, required in specifying geographic to its exact location. If there is not only with regard to spacing, but coordinates for single transmitting also in relation to True North, an antennas, further caution is neces- in these parameters could -tower arrays. When and Associates, error sary with multi *John H. Mullaney for a station to are in- Washington, D. C. make it impossible these directional systems build the array proposed in the volved, conditions change and the application. overall situation becomes somewhat more involved. Bearing and Azimuth The relation of an antenna site TRUE NORTH CENTER LINE to True North is expressed as a
MAGNETIC bearing or azimuth. The meaning NORTH of the word bearing can cause con- fusion between surveyors and radio it means OFFSET engineers. To a surveyor, TOWER AZIMUTH as a hori- REFERENCE the direction expressed POINT zontal angle from a point. The bearing can lie in any of the four of a circle with an axis quadrants `ANGLE BETWEEN CENTER LINES oriented to either True North or Magnetic North. Bearings are ex- in of their applicable Fig. 2. Parallelogram array. Fig. 1. In -Line array. pressed terms BROADCAST ENGINEERING I4
www.americanradiohistory.com Two important considerations in in a parallelogram. In this system, It has a pair of stars, on the side planning directional antenna sys- the angle between the two center of the bowl opposite the handle, tems are spacing and center lines. lines can vary appreciably, depend- known as the "pointers"-so-called The spacing of an array is the linear ing on the individual design. Ordi- because a line through them points distance between the center of each narily, the spacing between towers at Polaris. radio tower and a given reference on a given center line or azimuth To furnish engineers with the point or reference tower. Spacing will be equal, but unequal spacing precise variation of Polaris from varies from layout to layout, and is possible. The spacing between True North, a collection of astro- exceptions to spacing rules exist for towers in a parallelogram array, on nomical data called the Ephemeris each configuration. the different center lines, is usually 1962 has been prepared by the The center line of an array is the not constant, but could be in cer- Nautical Almanac Office of the azimuthal orientation of two or tain designs. United States Naval Observatory. more towers to a reference point or There are certain parallelogram reference tower. This orientation is configurations in which an offset Surveying expressed as a bearing in relation tower is located somewhere within Surveying is the science which to true north. As with spacing, cen- the array, but not on either center deals with the determination of ter line rules vary, and the condi- line. This so-called offset tower is relative position, or location, of tions for each configuration must generally to the center or off to the points on the earth's surface. The be taken into account. side of the center of the parallelo- determination of these parameters Ordinarily, if the array is in -line, gram. involves the art of measuring hori- a point midway between the end zontal and vertical distances and of Dog -Leg Array towers is used for computing the determining directions and angular used in geographic coordinates. In the case A third arrangement relationships by use of surveying is the dog-leg of parallelogram or dog-leg config- directional systems instruments. in 3. Here, three urations, the center of the array is array shown Fig. Some familiarity with surveying a triangle. used for determining the coordi- towers are laid out in terms and definitions will be of is most nates. One of the three towers value to the broadcast engineer who for the In installations where a different often selected as a reference is concerned with the planning of and number of towers is used for a day purpose of measuring distances an antenna system. A working, or It is or nighttime pattern, the reference determining orientation. pos- even a conversational, knowledge reference would not necessarily be the cen- sible, however, to use a of antenna surveying terminology tri- ter. But for purposes of providing point somewhere within the helps to improve communications -line location information to the FCC or angle. The spacings and center between station engineer and the this type of array the FAA, it is sufficient to use the orientation for civil engineer or surveyor. to same geogranhic coordinates for can vary in a manner similar in -line or a parallelo- Surveying Terms and Definitions both arrays. It is not reliable, how- those for an ever, for the civil engineer or sur- gram type. Culmination-Culmination can be de- fined as the passage of a celestial body veyor to use the same coordinates Polaris across the meridian of the place under for both arrays in establishing Extremely valuable in orienting consideration. All celestial bodies orientation, particularly if they cross every meridian twice in twenty- an antenna system to True North have different center lines. When four hours; the word transit is synony- is Polaris (or North Star), which is this condition exists, he must de- mous in this case to culmination. Cul- nearly on the extended axis of rota- mination for the purposes of surveying termine his own center references. tion of the earth. It is, therefore, is further divided as upper and lower almost True North, the limit always culminations. Upper culmination, or In -Line Arrays upper transit, means that the celestial One of the most prevalent direc- falling within 3°. body has crossed the meridian above tional antenna systems, the in -line Fig. 4 illustrates the location of the pole, whereas lower culmination, array (Fig. 1), consists of two or Polaris in relation to other con- Please turn to page 35 more towers which are spaced a stellations. Polaris, referred to as a certain distance apart on the same star of second magnitude, is useful bearing or azimuth. Where more in determining directions because it AN than two towers are incorporated in rotates around the celestial North an in -line array, the spacing be- Pole at a radius of approximately tween adjacent towers need not 1 ° 30'. Referring to the diagram, necessarily be constant. Ordinarily, it will be noted that Polaris is al- )er, in -line arrays use equal spacing be- most on a line between the middle tween towers on the same bearing; star of the handle of the Great Dip- however, unequal spacings are per and the brightest star of a con- sometimes used. stellation called "Cassiopeia," which has five bright stars in the form of Parallelogram Array a large W. REFERENCE Another common directional an- The Great Dipper, so called be- TOWER tenna configuration is the parallelo- cause of the outline formed by its REARING gram array (Fig. 2), which consists seven stars, rotates about 30° in of four or more towers arranged radius from the celestial North Pole. Fig 3. Dog -leg (triangular) array.
December, 1962 15
www.americanradiohistory.com tion, we could put the lower point on 1.0 and call it 100, because this TECHNICAL TALKS scale is logarithmic. Be careful not to open the dividers to 175 my/m, but go to 1750 mv/m in the second cycle. This point is found between Contour Calculations 10 and 20 on the graph (Fig. 2). These points will correspond to 1000 and 2000 after the factor of Every engineer who has ever Rules, results in the determination 100 is applied (100 times 1 my/m). opened his FCC Rules is familiar of a value corresponding to the de- with graphs 1-19A - groundwave sired contour and is thus read on field intensity versus distance for the graphs. Radiations Below 100 mv/m various conductivities, frequencies, Assume radiation at one mile to In the foregoing examples, we and powers. These are determined be 175 my/m: To find the distance read up for radiations of 100 mv/m for groups of frequencies, from 540 to the 500 uv/m contour of this or more. However, for strengths kc through 1640 kc, in which the station from the FCC curves (based less than 100 mv/m, you must read frequency of calculation is approxi- on 100 mv/m at one mile) multiply down from the conductivity line to mately the center. At the lower end the desired contour, in microvolts, the desired contour (Fig. 3). By of the band, where chances are by the ratio of 100/175. This be- placing one leg of the divider on ground conductivity is more pro- comes: the base line (100 my/m) and the nounced, the graphs cover only 20 100 X 500 other leg on the pertinent radiation, to 30 kc-whereas at the top of , or 285 60 uv/m for (A), you will 175 example band, where the effect is less, the Therefore, for a given conductivity move the ground conductivity line the last graph (Number 19-A) is at any frequency with a radiation of downward and obtain a distance to for 1600 kc and covers computed 175 my/m, the 0.5 mv/m contour the desired contour less than that 1560 to 1640 kc. will be represented by the 285 obtained with 100 mv/m (B). This uv/m contour. is an easy check on the accuracy of Power Adjustment the computation. If the graphical To find a given contour with any Each graph is computed for a distance to the desired contour is radiated power a divider is used as radiated power of 100 mv/m at one more than that to the same contour in Fig. 1. One leg is posi- shown with 100 my/m, the computed mile. If the radiated power is dif- tioned at the 100 mv/m line on the ferent than this, some interpolation appropriate graph (A). Remember- or computation is necessary. There ing that the graph uses a logarithmic Equivalent Distance Method are many ways of making an adjust- scale, the other leg is opened to Unfortunately, a complete con- ment. One, described in the FCC 175 read the desired power, say, tour is seldom involved with just mv/m again; this point will be be- one value of ground conductivity- tween the 100 and 200 mv/m lines sometimes there are as as six EDITOR'S NOTE: This article is the many on the graph. Now, maintaining this or seven changes. A typical example first in a new series by John Battison. slide the leg that Content each month will be planned to divider setting, is involved in going from the meas- provide the kind of information engi- was on the 100 mv/m line down ured conductivity to the M-3 values neers most often seek from a consultant. the pertinent conductivity curve un- when computing contours for an til the other leg rests directly above existing station, or for one on on the desired contour (B). The distance to the desired contour can 1000 then be read on the bottom scale 200 non (C). The ground conductivity line loo _- has been shifted to a new position so its intersection with the desired 10 contour value is read as though it -- was the original calibration for 100 mv/m radiation. 0.5 WwizA1e- No difficulty should be exper- 0.1 ma- ienced in establishing the divider as\ \ settings for any value of radiation. 0.01 For example, if the desired value is 550 my/m, the lower point is set 0.001 WI, on 100 mv/m as before and the
1 1 upper to 550. If it is 1750, the
(C) 1 0.0001 Ill lower point can be set on any unit dJ 100 1000 2000 line (1, 10, 1000, 0.1, etc.) and the 10 reading multiplied mentally by the desired factor for scale conversion. Fig. 1. Field intensity graph showing Fig. 3. Field intensity graph showing desired contour above 100 my/m. In the case of 1750 mv/m radia- desired contour below 100 my/m.
6 BROADCAST ENGINEERING
www.americanradiohistory.com MILES FROM ANTENNA
Q1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 1.5 ? 3 4 5 6 7 8 9 10 15 20 1,000 _ ...... ,. 1011. '-:Mic: ..' -:...... ,. eoo wäsiüi ii:::.; : Ind -:::- MUM WINO:34:3:::=3 GROUND WAVE FIELD INTENSITY NUNN iiM_ N._'uuuiMUMnldlu mnzNNmm111uwNlnnuam_ 600 . .. :{{ = _==_ass=3-=- ë-_ '={ .._..::siíäìi:co:-ii{''aii zEir-xxx ° VERSUS sª'x iï!!&!i:ii:xsi:: :i:l;g!¿:------500c_ e$èï ..`:-?ë-«,rs.= . r:.., s- ul_..iii3lliilli:ix DISTANCE M ,, M- _ . xM ,sz: ...... 1zk:- +ets:siiiiF 300 --i--:x 540-560 kc :: CCMPUIED FOR 550 KC, 1-15 - / AND THE GROUND CONDUCTIVITIES EXPRESSED IN MMHOS%M º " ":zé9iilï:a ßin FOR WHICH THE CURVES ARE LABELED 200 __._.:::_ ..::;1: ern_ :.:.r .i7il$l: lirmi i s,,: _ i:1tlNMái««w r .+I N IN.w wwrtl[ .N ,. leü' I.Ir1:I0li' ; a w«iwtlrxtlNNNwYrN/wirmwlN11/NNINN I1I Nm N ;n:,r,arw.3=._ .-; r-r r 7 B pp rr/INNINrrNINMNI NNll/rn yr 15 2 3 4 5 6 9 10 b5 óiaá/rrruruur_MiwrwrrinmrNnmi .- .. st 100 ?I.. `!? .3 7f--'-- --3.._..-.4- T _ ate:: '-t:r. ' ó«.::it3EióxiMtIt ..:...... :: . _..: s.-.w-'.C=r=:...:: EEE .-..-M 80 ==sH_ :a'N:::-ú[NN..:: iii1ai%i1.i'`:':-. '«üwT6. r.:«"w«:SidCi:1e-".-0Nll rmCL'rtli:..NNN M.iM.MtlNMN wNNN.:=i:: F w=:..-a / :1Pi«wwwwww\\g r.:Nrm bo _M-/MNrrNrN==i§:ifflN/ iNrwtlN.::. IIAoNNNmwwúÌlil!iliiÌlÑOroIIblNl!rNRrYr
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2 : r 1 -..' = isst:ea.:.n-!saoi.ses.m! ---mssa=at:eaes-!!I" am 0.8 ._ `:Q.:?«.'.:ii:ó.ì.'.\Z".«G.' :GCSB7L..T.=n6326:ß - r.ral.;!ml.eI!aMr. moe I®mCllmmmamemnamp 0.4 - 0.5 0.3 r _..- - .. I .. 4\ - _ 611S EL - 31 . K=mfi_=s=_aW=.T=.. 0.2 --- wl/.11.iS., . =:t^1': m:yC=. .,. k... .lwlII.11u. .W ..1N ::M: ' ! r ' }!!lllh!!Lt1lJ ;M .. . 0.1 lm111ltt1!:i '! í! .7:5iM6::.:úa ...... ::::M.==SCCi w E.súaa: 0.08 rNN.rrwá-wdC. SwiPi:.....« ...-á:á..Ni:%iìoa. im'wr.:rrNó á NMMNNrrwwrNÓ Ñ1Cy rN NN.mt\rry/yN-1.m /w/.1..\W\mIrr=«NÑ ÑMmd Ñéw cr 0.03 ''''':=2.7>MáÈç3AjS:?41 è:i.a - á -Ñ.--sr-3'-aa_: . ie -Yi:. :1=1» nng met. nona:0=C 0 03 .s Gw«.Ti - aai:-. Mw : .t :-::a..... - ..-e.- ._ - c xá' ...... -L £ì:.v::.._ =_:__r:wÿ.... ç3 rtss-sx gA _-_.'a E.Tc.:-aI s :r:aEaá«0.(2 --%:-. : "'::rlÑä.«Raic . ..Nm.. .;I==«áii^a': N0: 114 §11 :s~Ñl :-=ì " 11119 an:::: w_:tlNw:-ss::s ÁÑ ÌtÌm: 1=NrWHwwVm NNNrrrNNNN/rIMMNmÑ1Ytl IINNNN.NmrN11/N111rrnrl NY/IrMW1 3ia/nMrNNiNNNNÌIiw11NNM R_ Ii 0.01 %NNNMHM!rinIIIte!MPIIN;_,r.1á.9`IJNN íi 0.008 rÑ31lrri ttlüwlBil3tt11RiIÑCI.í.-JBiti-siliïirí\ts. 1sa.x1 íü'wïiiiaiTii,tìíiasss.NFtNNÑ tiawa9ialttNMBIll111t11ttR16lI - \Ng13N..\ iw,t , 11wufíiiiissalsssn.ia 0.006 wºllermnweleinrlletnilflnLesMNIM aGi/áR-TR- ili1: 0.005 s1'aRiiiNRiMTi,íis:z.._"i:,ii1liz:s_ S=R-.a3ni 0.004 ç.ii»fI 0.003 !rMn9nas_sf1wM R.-.=3L:iiÑiilwI C :5---.G: =L-- Ia 3.22:2-10 33 0.002 IsliÌri eiíïxiiñ laiïiii'"t 11#'31iEn9iix:m;BEll 4IIiGÑÑr1Ti ib:.s w.wM NM-iM1Ó1HÑÑ : .w\-Ñ ÑN«:iM: .....iR.wfII1 Ó\i,i...BO« w.II1[ , m Ñ 1 MNM:Ñ«4 Im1:NN N«:MNrtNNNiÑMCNNN.tNlwL }ñl }wM_uYiCMri tltlNN/,VIf _lili NAÑhÁÑ 0.001 s1mmanismumn Müa Ñ ImII Inxmlilsyrl 0.0008 sit17Mi:fiiisNWlli%g=it:iYYtiiiiti:rity irti?iC:i Ciw"ix Q1rllltlaltMYff; IINNIMHt1NINi. nilExe71 teagl11eR98.= (moos iueimetlNtilYla!!ni .. Rem __ i n - k. 00005 0.0004 ff=aa-::C:>9SffiEiME EMIR &J1$$_" - 0.0003 Ñ i3?aE lIA n, 0.0002 ffl .- .. NM1`S.CI _ 'i.i N, T_- t IC ::: . 1uirii.1tMew .1wnwPR\161.[ _04_474:- N.: *gems ,F 1 t hI I/IrNmIImN.r ämnIN. I1Ltl/1, 111111 4MÌrÑ arN é- pir / I 0.0001io . 1. N 1 15 20 25 30 40 50 fí60 70 80 90 100 150 200 300 400 500 600 700 1,000 1,500 24,100 MILES FROM ANTENNA Fig. 2. -Gm/ field intensity chart for 550 kc showing divìider at 1750 my f m. December. 1962 17 www.americanradiohistory.com 105° 107° (JoInS A-2) 106° 108° 44' 110° 109° fí,itLuiluu L H A K I e :_' In 0`I-_Sf'RINGS1 '' ' pertnopolis'h 1 ` 1 I._, 7 G . 43' E O N V ER S R .O N, A . N I eqa M O N T Caspery i:o DcugtaS ,' S U B 4 E1 -f, Lander 1 1 ! ; ; 'aihfinde.^ Rese.wóir ,. P L qKemmerer i! 1 R awlins, : E T W A T C A RclakSpring . ''eGréen Rive Ì arriie' ('J...3,.Y..i. N T'AI¡ 4N ailla "-; 1 -'.T D A G` --d E-T f'o412," Fart i n s UNAIN¡'. At PARK ¡ _ Lcrgmoit -- . A ' BOULDER mFÍ4tSu'' ur, Bouldero 40 I eh- e S r7.ngs ï Meeke a P-c .. t,.. Ni ' WOOO B L A \\ I `Gl:. `'. iCenYcal-1C' ... .- i téot'$etow ( 1 t \,1' AR CREEK c, -- - St) mil' _ _EerER9op.ÿ I G A R F` I recken /o ,'I { Larplay RR K 39° 'RGe rnd J etto G R D 105° I111!!I, 106° 107° (Joins C-2) 110° 109° 108° SCALE 1:2,500,000 260 MILES IO 0 20 40 60 80 100 120 140 160 180 200 220 240 I I I ! I I 1 I I 1 T I f 1 [ I I IIpIIIIIII I I 1 i I Fig. 4. Section of ground conductivity map (M-3). 18 BROADCAST ENGINEERING www.americanradiohistory.com Who helps you put superior spots before your sponsors' eyes? AMPEX Better local spots mean more money for you. need for specially trained film crews. Your own And now you can produce them with your V-R. staff can handle every job. Another Ampex ac- It's possible with the Ampex Electronic Edito cessory for better programming: Amtec-an operating with Ampex Inter -Sync. The Elec- automatic time element compensator that gives tronic Editor allows you to assemble, insert, you geometrically perfect pictures. For more add effects or make changes electronically until information write the only company providing you get just what you want to see-all withouE recorders, tapes and memory devices for every cutting an inch of tape. Add a Special Effects application: Ampex Corporation, 934 Charter Generator and you have every conceivable tran- Street, Redwood City, California. AMPEX sitional effect at finger-tip control. There's no Sales, service throughout the world December, 1962 I9 www.americanradiohistory.com which a proof -of -performance has mmhos, the signal will travel fur- been made. ther on the new higher conductivity. The FCC Rules give an example If the conductivity had been 8 all nd details regarding the Equivalent the way to 61.5 miles, the field in- First in Automation Distance Method; however, as in tensity for the distance would be any engineering application, there 0.6 my/m. However, it was not 8 is more than one way of handling mmhos all the way, so we subtract schafer changes. For an example of a popu- the difference between the 26 miles lar method, let's refer to Fig. 4. of 2 mmho conductivity, and the Here we see a section of an M-3, distance it would take at 8 mmhos with a radial along which it is de- to produce the same field. The only COMPLETE sired to compute the distance to the To determine the sign, consider 0.025 mv/m contour. The trans- the direction of the conductivity Automation System. mitter is radiating 200 mv/m at change -when going from a low to 550 kc. First measure the distance, a high conductivity, the difference from the site indicated by the cross is negative; when going from high at Steamboat Springs, to the center to low, the difference is positive. 1200E Program Automation of the first conductivity change line. Now all the positive numbers are The first distance is conductivity 2 added, all the negative numbers are for 26 miles (written 2 F 26). The added, and the two results are com- S-200 Automatic Spot Locator next distance is 35.5 miles of con- bined: Then we ductivity 8 (8 F 35.5). -27 +103.5 (3) have 15 F 34.5, and finally 2 out. -32.5 - 59.5 Automatic Audio Clock This is written: -59.5 + 44.0 out (1) 2 F 26 : 8 F 35.5: 15 F 34.5:2 We now find the distance at Automatic Program We now consult our appropriate which the 0.025 mv/m contour groundwave graph (Fig. 2) and find would fall if the conductivity were Preparation the point 26 miles on the 2-mmho 2 mmhos all the way is 160 miles. conductivity current. At this point Because there have been areas the field is 0.8 my/m. Now move where the conductivity is higher Cartridge Recorders the point of your dividers along than this, we expect the distance to this value to the curve for the next be greater than if the conductivity 8. Note the distance to had Remote Control conductivity been 2 mmhos for the entire Transmitter the same field that would be ob- distance. So we add the positive tained with 8 mmhos (the intersec- number obtained above, and arrive tion of the 8-mmho curve and the at a figure of 204 miles to the 0.025 horizontal field intensity line). mv/m contour. All products available through Write this figure above the distance If we had wanted the 0.5 mv/m to the first change (see calcula- contour, we would have checked to tion 2). see if it fell within the 2 mmhos COLLINS Adding this distance to that for area with our given radiation. If it which 8 mmhos is obtained (35.5), goes further than 26 miles, we we have 88.5 miles. Write this over would measure it using 15 mmhos, GATES the 8 and go along the 8-mmho and find that it falls at 130 miles. curve for this 88.5 miles. As before, This is within the total distance to move your dividers along the field the end of the 15-mmho region, so RCA intensity line to the next conductiv- we find the distance to the 0.5 ity line, 15. Write the value, 121 mv/m contour with a conductivity miles, above the 15 and add the of 15 mmhos and subtract the dif- 15 conductivity (34.5) to arrive at ference obtained at the change 155.5 miles. Write this above the points between 2, 8 and 15 mmhos: along the or direct from 34.5. Move the dividers (-27) (-32.5) 15-mmho curve for this distance 53 88.5 and then horizontally along the 2F 26: 8F 35.5:15F34.5 line until the next = 130 - 59.5 (4) schafer electronics field intensity = 70.5 miles to the 0.5 mv/m contour conductivity, 2, is reached. Write written description 235 SOUTH THIRD STREET this distance above the 2. Although the may sound a little complicated, BURBANK, CALIF. (-32.5) (2) once you try a few examples, you 52(-27) 88.5 121 155.5 (+103.5) 213 TH 5-3561 52 will find this method rather simple. : 2 2 G 26 : 8 F 35.5 : 15 F 34.5 out If each step is performed carefully, FAX RLJ Now return to the beginning of and accurate measurements are calculation (2); when our path con- made, correct results will he ob- ductivity changes from 2 to 8 tained. 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Also available is the MX-777,a six channel heads, professional 3" VU meters, automatic shut-off, automatic - tape lifters, an all all -transistorized stereo/monophonic mixer solenoid, feather -touch operated mechanism, electrical speed change, monitoring of that contains six matching transformers for either source or tape, sound on sound facilities, and an all -transistorized military plug-in balanced microphone inputs and recorder type circuitry for simple maintenance. 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For additional literature and name of All Sony Stereeorders The Tapeway to Stereo nearest franchised dealer write Superscope, .'eadyl SUPERSCOPE are Multiplex Inc., Dept. B, Sun Valley, California. www.americanradiohistory.com PLANNING A NEW FM by Lloyd M. Jones" - PART TWO. Factors that go into a good audio system, and some pitfalls to avoid. STEREO STATION Audio Control Boards to hold the power supply, limiter The teletype machine should be The selection of audio control amplifiers, frequency and deviation reasonably close to the control room boards will depend to a great ex- meter, monitor receiver and ampli- and studio for functional operation; tent on whether a monaural or fiers, audio patch or switching pan- yet for noise considerations, it stereo station is to be built. Stereo els, and an off -the -air RF amplifier should be kept at least two walls broadcasting requires a dual chan- to drive the frequency and devia- away. All audio circuits must be nel board-one using individual tion meter if your transmitter is to balanced (not grounded on one side) faders, or one of the newer type be remote controlled. and should be 600 ohms or less. with coaxial dual faders. If discs Cabinets must be provided with Microphone lines must be well are going to be played, the latter cool -air intake at the bottom and shielded and in separate conduit or level is preferred, since it simplifies man- hot-air exhaust at the top. If ex- gutters from medium and high ual operations. haust fans are used in the area, audio circuits. It is very important make sure they do not cause any to keep all audio circuits away from Also, for stereo use, be sure to sound or rumble in the control the teletype lines! Run the teletype get a board with two VU meters. room or studio. Consider everything lines into the building through con- The control -board power supply in the control room and studio as duit. These lines carry sharp im- should be external to minimize the potential noisemakers, and sound- pulses which can get into low-level heat in the console cabinet. One or proof all six sides of each room. lines regardless of shielding. Be ex- two enclosed 7' racks can be used Even fluorescent ballast -transform- tremely careful of ground -loops ers are noisy, and there is noise which can cause hum-run 3" cop- 'Chief Engineer, KMUZ, Santa Barbara, Cal. from tape decks, turntables, etc. per strap in the gutters to each piece of equipment, and ground each to the console. The shield of each audio cable must also be grounded to the audio console. With the exception of mic- rophone cables, where the shield is used to ground the microphone case, all shields should be left open at the end opposite from the audio console. In large stations having several studios and cabling up to 200' long, ground -loop voltages of 1/4 volt, 60 cps are not uncommon and obviously can cause severe hum if the circuit is completed. Limiting Amplifiers In general, suppliers of audio con- soles will also supply the limiting amplifiers, one of which should be in each channel. Set the View of control room looking into the studio. The console enclosure is a installed one-piece unit fabricated by a local cabinet shop. The audio console is a gain reduction no higher than about Collins 212-E Dual Channel with a full compliment of preamplifiers, dual 5; excessive limiting will only re- limiters, and a monitor. It feeds the left channel when any key is in the Riding up position, and the right channel when any key is down. The small control duce the stereo separation. panel to the left of the console provides switching to turn the clock control gain is necessary to keep the audio on and off, and to start and stop the main automation tape decks. The panel level within the proper limits. Lim- to the right controls the stereo tape deck, mounted at the top of the rack, used to record stereo albums, programs from the studio or control -board micro- iting amplifiers do not chop off the phone, and special interviews from the telephone; this stereo deck can also audio signal above a certain preset be used with the automation equipment. Mounted in the rack below the tape level; they only start reducing gain deck are a monitor amplifier, silence sense deck, and 25 -cps generator for cuing the recorded tapes. as the limiting action begins. For 22 BROADCAST ENGINEERING www.americanradiohistory.com example, for every 3 db of signal belt or flexible shaft. The rumble to feed the turntable and preampli- fed into the limiting circuits you can should be guaranteed more than 30 fier directly into the tape recorder expect an output rise of approxi- db below program level; 40 db with either patch cords or switch- mately 1 db. Thus, the attack and would be even more desirable. ing. Do not connect them through release time of limiters should be Be careful to choose a stereo the main audio board. The pre- adjusted to suit your needs. pickup head guaranteed to have no amplifier should be used with the Certain brands of limiters will measurable or aural AC pickup, and function switch set in the RIAA perform an extremely important use great care in selecting the arm. Flat position. To facilitate weekly function for the stereo broadcaster It must be nearly perfectly balanced maintenance, obtain one of the -limit only the high frequencies. with minimum friction in the lateral many good stereo test -records. We This type of limiter has been and vertical directions. Since you use the No. 103L/ 105R Stereo- used in sound recording on film, probably will not be playing the phonic Sweep -Frequency test rec- tape, and discs for several years discs time and again, it is permissi- ord produced by Pacific Trans- and is essential to FM stereo broad- ble (and often desirable) to use a ducer Corp. This disc sweeps from casting. It does not destroy the high slightly greater tracking pressure 70 cps to 15,000 cps twenty times frequencies, but reduces them on the when recording from discs to tape. a second, has marker pips at 1, 3, high volume peaks only. At the Many of the available broadcast 5, 10 and 15 kc, and provides a same time, it permits the lower fre- pickups have a nominal output im- sync pulse for the oscilloscope. By quencies to pass at high volume pedance of 47,000 ohms to feed an employing such a record you can levels, thus producing the desired equalizer or the 600 -ohm terminals see your equalization as a continu- effect of greater dynamic range. of the audio console; either arrange- ous pattern. Set the equalization With this type of limiter, the aver- ment results in mismatch and inade- controls on the preamplifier first for age volume increase to the listener quate reproduction. To regain "mel- one side (left), of the record, then is about 6 db higher than without low and crisp" music quality, the the other (right), and the job is it. High frequency cross -talk, due stereo head must be fed into a pre- done! to overmodulation from channel to amplifier having a matching input - Stereo phasing can also be check- channel, or from channels to back- impedance. Most of the stereo pre- ed at any point in the studio/trans- ground music (SCA), is virtually amplifiers made by reputable manu- mitter equipment by noting the di- eliminated. facturers, kits or wired, will do an rection of the marker pips in both excellent job. The only modifica- the right and left channels. If the Microphones tion necessary is the installation of pips are the same (either positive There are many types of micro- a matching transformer, approxi- or negative) in both channels, the phones available, several of which mately 20,000 ohms to 600 ohms, in system is in phase. will do a good job. To be prepared each of the outputs. Any transform- Monitoring Equipment for the majority of situations, use er similar to the Triad JO -23 speci- microphones with a frequency re- fications will work very well. A stereo monitoring system sponse of 50 to 15,000 cps. If good We have found it best, when should be provided in the control low response and physical place- transferring disc recordings to tape, room, and in certain offices. A good ment causes the announcer's micro- phone to be susceptible to low fre- quency rumble, install an RC net- work in the preamp to reduce response to about 200 cps. Turntables and Tape One or two turntables will be needed for playing disc records on the air. If a minimum of tape equip- ment is used, you may need three or four turntables; however, tape machines are carrying the bigger load in today's operations. Stereo tapes can be purchased prerecorded or made in your studios from your choice of stereo albums. Remember, however, recording from records to tape requires turntables which are free from wow and low -frequency rumble and are mounted in solid, heavy enclosures. (With the good low frequency response of FM sys- tems, rumble is not tolerable.) Since The six stereo decks in racks 1. 2, and 3 are controlled by the equipment in turntables meeting these require- racks 4 and 5. Rack 4 contains the left -channel controls, silence sense, cue - dot, and 25 -cycle unit, as well as the clock control. Rack 5 contains the relays ments cannot usually be directly that switch the right channel; they are essentially in parallel with the relays driven, select one that employs a that control the left channel. December, 1962 23 www.americanradiohistory.com stereo tuner, stereo preamplifier, can afford; the automation circuitry of musical selections, but the con- and dual power amplifier are by each supplier has its own fea- sequence of this condition depends needed for this purpose. Up to three tures and all do a good job. It is on the individual operation and its or four 8 -ohm speakers can be fed best to install enough decks to run application. from the 4 -ohm output tap in each automated for at least six hours. Give considerable thought to the channel without serious mismatch. One transport should be used for layout of your control room, studio, Line transformers are required for recorded promos and/or announce- equipment room, teletype room, reproduction down to at least 50 ments, and must be set up to stop shop, offices, and storage rooms. cps in voltage distribution systems, automatically. This can be done by They must be functional, and not or when some impedance other than means of the "cue -dot" system. A too small. Of prime importance is 4 ohms is desired. To avoid resist- photocell is positioned to sense adequate ventilation, air condition- ance losses, No. 14 wire should be clear spots on the tape, where the ing, and soundproofing in the studio used for speaker wiring where lines oxide has been removed with lac- and control room. must be long and in systems where quer thinner. By using a stop watch, Conclusion transformers are not used. place the cue -dots at intervals of 65 seconds, for example. This will With consideration of the many General System give about 70 one -minute (or less) points discussed here, plus the many It is possible to broadcast twenty- spots on a 1,200 -foot reel playing others which will appear as you four hours a day with live news at 71 ips. When an announcement proceed, many headaches can be every hour between six A.M. and is played, the tape will continue run- avoided, and much wasted money as midnight, live as well as recorded ning until the photocell -relay circuit well as a good deal of time can be commercials, promos, and studio stops the machine, leaving it all cued saved. As a result, the FM Station programs, through the use of re- up for the next announcement. Oth- that is built will remain modern and mote transmitter -control and auto- er systems, including 25 -cycle tone able to broadcast very nearly tech- mated tape -equipment. Look over and silent-sensing, may also be em- nically perfect entertainment for the automation equipment of sev- ployed. many years to come. Pioneering a eral manufacturers before you de- The other decks can play music new medium can be exasperating. cide which will best suit your needs. with a silence -sense, or 25 -cycle But if you are going into stereo FM We strongly recommend that you tone system automatically and in broadcasting, do the initial job cor- select a system which includes the various sequences. This technique rectly, and you will find the rewards highest quality tape transports you essentially precludes the announcing are many. spotmaster CARTRIDGE RECORDER WITH BUILT-IN EXTRAS 500 compact recorder -playback unit Compact models for flexibility Rack mounted models with chassis slides Sealed plug in relays a Plug in tape decks Unitized amplifiers Heavy Duty Hysterisis Synchronous Motor Rated for continuous duty 505 compact playback unit Field tested-field proven 500 compact recorder -playback unit Guaranteed for one year! BROADCAST ELECTRONICS 8800 Brookville Road, Silver Spring, Maryland, JU 8-4983 Sold Nationally by: VISUAL ELECTRONICS CORP., 356 W. 40th St., N.Y., N.Y. 505R rack mount playback unit CANADA: Northern Electric Co., Ltd., 250 Sidney St., Belleville, Ontario. 5Q0R rack mount recorder -playback unit 24 BROADCAST ENGINEERING www.americanradiohistory.com www.americanradiohistory.com CAMERA -TUBE by Bill Kessel* - Here's a simple 30 -cps oscillator which provides a ALIGNMENT rocking -focus signal for camera adustment while in use. USING 30 CYCLES Beam alignment of cameras using tern. Two of our supervisors, Walt otherwise indicated. The input sig- the 5820 image orthicon has never Baxley and O. G. Kelly, devised nal is composed of 60 -cps vertical - been a real problem-stopping the and built a generator which has per- drive pulses which can be looped orth spot is a simple and reliable formed this function efficiently for through or terminated at the unit. procedure. But how can vidicons be many months. The circuit was designed to pro- aligned? And what technique can duce, at its output, a 30 -cps sub- be used with the newer image orthi- Circuit multiple of the input. These output cons that employ a field mesh? pulses can be fed to any number Some other means must be devised The simple two -tube generator of cameras in a manner similar to for proper alignment of these tubes. circuit shown in Fig. 1 consists of that shown in Fig. 2. The pulse One way to quickly and accu- a 12AV7 tube, which is used in the amplitude is controlled by the 25K rately accomplish this adjustment is input and output -amplifier stages, potentiometer in the output circuit. to rock focus at a 30 -cycle rate, and a 12AU7, which is employed as When switch S1 is closed, the pulses while observing a suitable test pat - an astable multivibrator. All resis- are applied to the center arm of the *Chief Engineer, KTVT, tors are the 1/2 -watt size, and all beam -focus control, thus rocking Fort Worth, Texas. capacitors are 400 -volt units unless the focus at a 30 -cps rate. 285 VOLTS DC @ 18MA 220K 3900 0 1 WATT 447K 100V VERTICAL .01 V1B DRIVE 200V 75mmf 1/2 ; VIA 12AV7-012AV7-® 1/2 3oti 12AV 7 470 100m d § l m eg K V2B @ 50V 1/212AU7 §lmeg ; 2200 0 25K 1 20mfd 27K T@ 150V Fig. 1. Circuit of 30 -cps pulse generator. 26 BROADCAST ENGINEERING www.americanradiohistory.com ALL WRAPPED UP IN YOUR WORK? Free yourself for just 20 seconds to check Mechanically tested for coating thick- the advantages of using RCA Red Seal ness, anchorage, layer -to -layer adhesion, Magnetic Tape Products Marketing Magnetic Recording Tape: aging, cupping, slitting. (It's got to mea- RCA Victor Record Division 155 East 24th St. Developed by RCA sound engineers for sure up!) New York 10. N. Y. BE use. (They insist their own professional Precisely controlled to give every inch Please rush me specifics on RCA Red Seal on the very best!) of tape the same magnetic properties, the Magnetic Tape including all essential Manufactured in the country's newest, same recording -bias characteristic. (So physical and magnetic characteristics. most modern plant. (Everything's up-to- you can use tapes interchangeably!) date in Indianapolis!) Take another 20 seconds to make your NAME Supervised from basic oxide formula- job a whole lot easier-fill in the coupon TITLE on this great new tape! tion to finished tape by skilled engineers. for specifics COMPANY (All sticklers for perfection!) ADDRESS Quality control tested for frequency re- sponse, distortion, drop-out noise, print RCA VICTOR CITY ...... ZONE ...STATE through. (Very rigid tests!) eiThe most trusted name in sound L December, 1962 27 www.americanradiohistory.com TO OTHER So Video and Pulse EQUIPMENT ij SWITCH SI 1.0 Stot. DISTRIBUTION FROM OUTPUT OF BEAM FOCUS EQUIPMENT GENERATOR CONTROL ON CAMERA CONSOLE Fig. 2. Input circuit to camera consoles. Operation When the pulses are applied to a camera, a double -image pattern will be displayed on the monitor. The two images will be offset from each other in proportion to the de- gree of beam misalignment. To ad- just a camera with a cross -hatch pattern, for example, the alignment A complete transis- controls are moved until the pairs torized video and of horizontal and vertical lines are pulse distribution sys- tem in convenient as nearly coincident as possible. plug-in Module con- Once some experience is gained with struction. this technique, almost any type of This basic 51/4" rack to mount frame contain- test pattern may be employed ing its own Plug-in obtain optimum alignment. power supply can pro- vide 48 pulse outputs Our unit was built on a 19" chas- r 36 video outputs. sis so that it could be rack-mounted desired, pulse and adjacent to vertical -drive and power video distribution am- plifiers can be put in equipment. The output is fed the same frame utiliz- through RG 59/U cable to vidicon ing the same power and image-orthicon camera con- supply. soles. This generator is particularly valuable for use with vidicons-by throwing a switch you can tell at a glance whether or not the tube is aligned. If it is not, the amount of misalignment can be readily deter- mined. Modular Plug-in Construction High Input Impedance Identical Multiple Outputs Maximum Output to Input Isolation Plug-in Power Supply with individual About the Cover voltage regulator on each amplifier Simple Stable Circuitry Shown on the cover this month are Designed For Reliability central-office patching bays typical of Minimum Cost per Output those operated by the American Tele- phone and Telegraph Company's For the best and most modern broadcast systems Long Lines Deparment in many large and supplies, look to VISUAL-your SOURCE for cities. Such equipment is employed in Superior Equipment from Specialist Manufacturers. the major nation-wide radio- and television -signal relay system. The in- Write today for complete technical specifications. stallations, which are designed for broadband operation, make use of VISUAL ELECTRONICS microwave transmission techniques CORPORATION with high -frequency L -carriers. (Photo courtesy A.T. & T. Photo Service.) Keeps You in View! liN3Se west40th street new york 18, n. y. pennsylvenis 28 BROADCAST ENGINEERING www.americanradiohistory.com Make lip -sync with the world famous NAGRA III The NAGRA Ill is the self-contained professional tape recorder assur- ing independence, professional standard of performance, reliabi- lity, convenience and ease of use. 1/ Input No.2 and ATU m.p.s. Pilot sync pulse input NAGRA Ill B: list price in the us $1045.- NAGRA III NP with pilot sync pulse head: list price in the US $ 1095.- Twelve 1.5 V D type D=_Ils\ SLP SYNCHRONIZER Input No. 1 for conventional list price in the US $ 295. - dynamic microphone Performance The NAGRA sound -transfer system 30 16.000 1.5 DB : automatic speed correction and 58 DB ASA A signal/noise pilot playback 0.1% peak wow and flutter Works from -13° to 122° F NAGRA III SLP Micro imp.: 50-200 Ohms mains power 60c/s sound Servo -loop speed control: 15", 7.5" (CCIR/NAB), 3.75" Write for brochure and new dealer list to KUDELSKI 6, ch. de l'Etang, Paudex - Lausanne, Switzerland www.americanradiohistory.com used while the program was on the ENGINEERS' EXCHANGE air. The same setup will operate two-way, of course, with two signal MI Ill IM BB MI generators and a pair of AM radios. CHAIN DUMMER FIELD CAMERA Emergency Transformer B[ Replacement O O o by Jack Alexander, Consultant, u Washington, D. C. Recently, our transmitter went off with a big bang, and we could not RECEIVER get it back on the air by means of AT STUDIO OR TRANSMITTER the remote control system. At the O O O O transmitter site, we found that every TO SWITCHER time the B plus went on the main breaker tripped. FOLDED DIPOLE Quick checks with a VOM indi- IN FIELD cated a short circuit from primary to secondary, on the rectifier bank. YAGI ANTENNA Isolating the defective transformer was of no value because our B plus went directly to ground. We needed another transformer in a hurry. Fortunately, one of our an- nouncers was a ham and happened to have a transformer we felt would work. We insulated the unit from the transmitter rack with a large dry board, and connected it in place of the faulty transformer. When the power was switched on, it worked! Of course, some of the transmitter "insides" were hanging out on the Carrier Current the line and applied audio from the floor, but only for the short time console amplifier cue to the exter- before a new transformer arrived. Cue Line nal modulation terminals. by Jack Alexander, Consultant, The signal generator and a stand- Washington, D. C. ard AM receiver at the remote site A Remote TV It is possible to use a DC remote (in this case, a club) were tuned to Pickup System line for cueing while on the air. approximately 600 kc. By position- by Torrance Downey, Chief Engineer, We found that the line to one ing the receiver at the operating Voice of Cape Henlopen, Del. of our local dance band pickups position near the remote line, the was a DC pair without RF currents, modulated signal was picked up The average small TV station has and with no low-resistance shunts. and detected in the normal fashion. little or no money to spend for To provide continuous cueing, we We thus had a perfect RF car- remote -pickup microwave transmit- connected an old RF signal gener- rier -current cue line from studio to ters. Yet there are many times when ator, set for maximum output, to remote location, which could be such a device would be quite valu- able to such an operation. Some years ago, DuMont intro- STUDIO CONSOLE EXTERNAL R F SIGNAL D C BLOCKING a device the DuMitter. MOD. TERM GENERATOR duced called CAPACITORS 2000 TERMINAL It is, in effect, a very low power O 2 BLOCK television transmitter. The video is TALK BACK 9,30©9 MICROPHONE Ì fed into low -power amplifier EE a RF which an of about CUEi AMP.] provides output o !I 0 OUTPUT 0 2 watts on channel 2 or 3. This device can be used both as a line TERMINAL amplifier and a transmitter. BLOCK On one occasion, we wanted to REMOTE LINES televise the local high school foot- ball game, but had no way get- REMOTE AMPLIFIER of ting the signal from the field to our A M RECEIVER transmitter. The local power com- o ([[[(![l[ o © pany, in their usual generous way, gave us permission to string half a 30 BROADCAST ENGINEERING www.americanradiohistory.com mile of surplus RG -11 cable on their utility poles-and we were in business. Our field camera fed into the DuMitter which, in turn, fed the RG -11, on channel 2. At the other BAUER TRANSMITTERS end, the signal was passed into our transmitter. This method resulted in Provide Top Performance With Minimim Maintenance a somewhat inferior picture, but enabled us, for the first time, to put our high school football team on ill / w A television. The audio, of course, came along the telephone lines. Another way of using these versa- tile units is as air transmitters! The output can be fed into a folded dipole antenna, and directed to a Yagi at the transmitter. If you are working on your own property, this is legal, as far as I can determine- provided power does not exceed that permitted by FCC Rules. Make Your Own Station ID's on Film by Herb Green, Consulting Engineer, Paramus, N. J. 1,000 WATT FM 10,000 WATT AM Though 35 -mm slides are fine for Ste -en -Ready. Simple design. Ceramic tubes in PA and Mod Ater. 12,500 watt output capa- TV station ID's, a moving scene, BuiR-in load. Factory assent led bility. Lowest power consumpticn-high efficiency PA and modern which makes the presentation more or fit Form. des gn. Only 9 tubes -5 types. interesting, is often desired. Use a 16 -mm movie camera that will take 100 feet of single perforated film. Load the camera with reversal sound film, and expose it all, in one continuous run if pos- sible. We took our camera up in an airplane to shoot the transmitter and surrounding area. Next, take the camera into a dark room, rewind, and again load the camera with the same film. This time, shoot a card lettered with the station call, or another suitable title. (If your previous scene was dark, use white letters on a black background.) Again expose the en- tire 100 feet of film without pausing. The next step is to have an an- nouncer record the ID on tape for AM 1,000/250 WATT AM two and three-quarter minutes, 5,000/1,000 WATT d State The famous Model 107. Leader without pausing more than five sec- 6,000 watt output capabil ty. Continuous metering. Sol system (standard ii all Bauer transmitters). Fcol-proof in the field. Easiest to Buy. phrases. Send this rectifier onds between circuit protection with tally-light/overload relay system. Low Easiest to Operate. Factory as- a tape and the film to processsing power consumption-economical to operate. sembled or Kit Form. laboratory, and have them transfer the recorded ID to the sound track. WRITE FOR THE COMPLETE ENGINEER NG STORY TODAY! When the film has been pro- cessed and returned, you will have 100 feet of positive sound film with your station ID recorded both vis- ually and aurally. The 30 short ID clips can be used over and over, BauerELECTRONICS C O R P O RATI C I\ and attached permanently to par- 1663 Industrial Road, San Carlos, California Area Code 415 591-9466 ticular films and announcements. December. 1962 3I www.americanradiohistory.com 1962 SUBJECT Listings by subject, article title, and month of publication - for articles REFERENCE INDEX published January through December, 1962 AM RADIO -part 1, levels Aug. -part 2, design Sept. part 1, tests Sept. Limiting -part 2, design Sept. Conference part 2, monitors Oct. Audio Limiting Action and AUTOMATIC CONTROL The Sixteenth Annual NAB New station AGC Action June Automation Engineering Conference Some Do's and Don'ts for International Operation Automation, Tape Control, May FM Stereo Sept. The Voice of America . Jan. Stereo Claim Limelight at FCC rules Planning a New FM Stereo Maintenance, transmitter '62 NAB Show May New FCC Actions of Special Station Radio Transmitter Automatic Time Interest Engineers Feb. -part 1, transmitter Nov. Maintenance Injector Oct. Research, ionosphere -part 2, studio Dec. -part 1, tests Sept. Conelrad alarm Ionization Research With Proof -of-performance -part 2, monitors Oct. A News Teletype Automatic Simple Tools July Practical FM Engineering -part 3, schedule Nov. Conelrad Alarm Aug. Signal strength and radiation -part 3 April ANTENNAS, TOWERS, CAMERAS AND TUBES contours GENERAL AND PROPAGATION Alignment Do You Understand DBU's History, Gates Radio Directional systems Camera -tube Alignment and DBK's? Nov. As Old as Radio July Installing a Directional Using 30 Cycles Dec. Transistors '62 NAB Engineering Transistor Antenna Nov. Color Audio Amplifier Conference Fundamentals The Development of Image Circuits The Sixteenth Annual NAB Practical FM Engineering Orthicon Camera Tubes For -part 1, levels Aug. Engineering Conference -Dart 2, design Sept. -part 1 Feb. Color Programming July May Ionosphere CARTRIDGE TAPE EQUIPMENT '62 NAB Show Ionization Research with Control Alignment generator, camera- Automation, Tape Control, tube Simple Tools July Automatic Control For the Stereo Claim Limelight at Mounting of antennas Viking Cartridge Tape Camera Tube Alignment '62 NAB Show May Using Practical FM Engineering Machine April 30 Cycles Dec. LEGAL CONSIDERATIONS -part 2 Mar. Time signals Amplifier, noise suppression Directional arrays Radiation contours Automatic Time Program Gated Noise Sup- Forensic Do You Understand DBU's Injector Oct. pression Amplifier April Engineering Jan. Conelrad alarm device and DBK's? Nov. CONSTRUCTION Installing a Directional Rules and regulations A News Teletype Automatic Antenna Nov. Alignment generator for The Conelrad Alarm Aug. FCC rules New FCC Rules Affect camera tubes You Generator New FCC Actions of Special Nov. Camera -tube Alignment Tuning New Emergency Interest to Engineers Feb. Using 30 Cycles Dec. A Generator July The New FCC Rules Composite Antenna Antenna tuning Affect Tuning Unit Remote amplifier You Nov. Sept. A Composite Antenna WINC Satellite Practical Application of FCC AUDIO Tuning Unit AND AUDIO Sept. Remote Unit Oct. Engineering Rules Frame -locking generator Dec. TAPE Translators Proof -of -performance Frame -Lock Device for the AGC Some Television Translator Practical FM Engineering Audio Limiting and AGC Ampex VTR Nov. Notes Feb. Paging system -part 3 April Action June Transmitter Technical Add a Paging violations, Amplifiers System to New 20 kw FM preventing Your Monitor Transistor Audio Amplifier Nov. Transmitter Aug. Preventive Maintenance Phase -shift check unit of a Circuits Tuning unit Different Kind Feb. Measuring Phase Shift Be- -part 1 levels Aug. A Composite Antenna tween Stereo Channel Oct. MAINTENANCE -part 2 design Sept. Tuning Unit Sept. Noise, eliminating Disc records, stereo Remote unit Oct. Video tape editing device WINC Satellite An Approach to Cleaner Stereophonic Phonograph Electronic Video Tape Sound Records, Phase Remote Unit Oct. Editing Relations, Sept. -part 1, grounding Mar. and Stereo Broadcasting Tape control device Video tape frame -lock unit Automatic Control For the part 2, shielding ...June Aug. Frame -Lock Device for the Schedule Studio Viking Cartridge Tape Maintenance Ampex VTR Nov. Preventive Maintenance for Audio Studio Maintenance Machine April FM RADIO Tape the Studio Dec. -part 1, tools and Cuer Antennas An Automatic Tape Studio checks June Practical FM Engineering Cuer Mar. Audio Studio Maintenance -part 2, testing July -part 2 Mar. Time signal device -part 1, tools and -part 3, cleaning and Disc records, stereo Automatic time injector Oct. checks June schedules Aug. Stereophonic Phonograph -part 2, testing July Tape Cueing ENGINEERING AND Records, Phase Relations, -part 3, cleaning and An Automatic Tape THEORY and Stereo Broad- schedule Aug. Cuer Mar. AGC, audio casting Aug. Television systems Automatic Control for the Audio Limiting and AGC Fundamentals, engineering Television System Viking Cartridge Tape Action June Practical FM Engineering Maintenance Machine April Amplifiers -part 1 Feb. -part 4 Jan. Transistors Transistor Audio Amplifier Maintenance, transmitter Transmitters Transistor Audio Amplifier Circuits Radio Transmitter Radio Transmitter Circuits -part 1, levels Aug. Maintenance Maintenance 32 BROADCAST ENGINEERING www.americanradiohistory.com NEW... FROM CONRAC A REGULATED 8" MONITOR AND SCOPE HOUSING FOR DIRECT INSERTION IN THE STANDARD 13" RCA CONSOLE Available in two models: CTA8/TU is designed to mount the Tektronix 527 Scope. The CTA8/RU is designed to mount the RCA TO -2 Scope. DIVISION Glendora, California (CONRAC GIANNINI CONTROLS CORPORATION Telephone: AREA CODE 213.335.0541 December, 1962 33 www.americanradiohistory.com -part 1, tests Sept. New Traffic Control System part 2, studio Dec. TRANSMITTERS -part 2, monitors Oct. for Radio Spots July Phase measurements Eliminating signal -part 3, schedules Nov. Measuring Phase Shift contamination Video tape recorders PLANNING STATIONS Between Stereo An Approach to Cleaner Television Tape Antenna height and erp Channels Oct. Sound The New FCC Rules Fundamentals -part 1 Mar. -part 5 June Affect You Nov. STUDIO FM Form Application 301 Cleaning and mechanical New 20 kw FM MOBILE AND REMOTE Practical Application of FCC maintenance Transmitter Aug. Radio mobile unit Engineering Rules Dec. Audio Studio Maintenance Practical FM Engineering WINC Satellite Remote 3 Aug. FM stereo -part part 1 Feb. Unit Oct. Some Do's and Don'ts for Fundamentals of maintenance High power Television tape unit FM Stereo Sept. Audio Studio Maintenance The Voice of America...Jan. Mobile Video Tape Planning a New FM Stereo -part 1 June Maintenance Installation-TWW Station Maintenance, preventive Radio Transmitter England Dec. -part 1, transmitter Nov. Preventive Maintenance for Maintenance -part 2, studio Dec. the Studio Dec. part 1, tests Sept. NOISE, GROUNDING, Multi -tower arrays Measurements -part 2, monitors Oct. AND SHIELDING Installing a Directional Audio Studio Maintenance - -part 3, schedule Nov. Eliminating unwanted signals Antenna? Nov. -part 2 July Microwave Preventing Signal Translators Two Hop Educational TV Contamination Oct. TELEVISION Some Television Translator Microwave System Jan. Grounding Color Notes Feb. Translators An Approach to Cleaner Stereo -Color Some Television Translator Violations, avoiding technical Sound Television July Notes Feb. Forensic Engineering Jan. -part 1 Mar. The Development of Image Equipment noise Preventive Maintenance of a Orthicon Camera Tubes for VIDEO TAPE Practical FM Engineering Different Kind Feb. Color Programming July Editing Electronic Video Tape -part 3 April Maintenance STEREO Editing Sept. Shielding Television System Disc records Frame -Lock Device for the An Approach to Cleaner Maintenance Sound Stereophonic Phonograph Ampex VTR Nov. Records, Phase Relations, -part 4 Jan. -part 2 June Fundamentals Suppression and Stereo Tape equipment Television Tape Electronic Video Tape Program Gated Noise Sup- Broadcasting Aug. Fundamentals pression Amplifier April FM station, establishing new Editing Sept. part 1, basics Feb. Some Do's and Don'ts for Frame -Lock Device for the -part 2, basics Mar. OPERATIONS FM Stereo Sept. Ampex VTR Nov. -part 3, recording April International radio Planning a New FM Stereo Translators -part 4, playback May The Voice of America.. Jan. Station Some Television Translator -part 5, testing June Traffic control -part 1, transmitter Nov. Notes Feb. -part 6, heads July The new Electro -Voice Model 654A can replace to D up three of your 2217 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. ft's also an easy -wearing lavalier, with wide range and plenty of VALUE! 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 Acoustalloycf dynamic diaphragm that wilt take the hardest accidental abuse, yet still deliver peak -free natural response. New Acoustifoamm 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 654A includes stand adapter and n;rci lanyard. List price $100.00. ELECTRO -VOICE, INC., Commercial Products Division, Dept. 1221V, Buchanan, Michigan ge-t,tereicz Subscribe today to "Microphone Facts", fact filled, free series on modern microphone techniques. Request on studio letterhead. 34 BROADCAST ENGINEERING www.americanradiohistory.com DA Antenna Systems distance by the solution of similar arranged so that angles to a distant triangles, and involves the use of a point are observed from the ends of (Continued from page 15) transit and a level rod with two the base and translated directly into targets. distance units. or lower transit, means that the celes- The range finder is an instrument Subtense is the method of deter- tial body has crossed the meridian which employs a known base, and is mining optical distance by means of below the polar axis. Horizontal distance-Horizontal distance (THE BIG DIPPER) refers to the distance between two MAJOR) points in surveying. (URSA GREAT BEAR) Local time-Local time is the true time (THE at given any location. All points hav- POINTERS ing the same longitude (lying on the same meridian) have the same local time; local noon is the moment of the (THE LITTLE DIPPER) sun's transit over the meridian on (URSA MINOR) which a place is located, and is only (THE LITTLE BEAR? used for astronomical purposes. *- Mean solar time - The typical watch ,+ shows mean solar time. The expres- , *' sion mean time is derived from a mean solar day, which can be defined /". as the average time between two suc- cessive upper transits of the sun. Optical distance - Optical distance is a POLARIS distance measured optically, depend- ing on a length from a small base at one end and the angle subtended by that base at the other. The base can be located at the observer's position, (CASSIOPEIA) I or at the far end, and may be vertical LADY IN THE CHAIR) or horizontal; the base and the sub- tended angle may be fixed or variable. ,* Typical methods of determining op- I_ * tical distance are by use of stadia, range finder or subtense. Stadia is the method of determining Fig. 4. Celestial diagram showing locations of the Big Dipper and Polaris. PORTABLE EQUIPMENT FOR N E W STATIONS ON THE MOVE A10 AUDIO CONSOLE REMOTE, PRODUCTION OR MAIN STUDIO The unique Sparta A-50 Portable Studio handles all of these jobs with ease. simply un -screw the steel tapered legs, clip them inside the bench, latch the bench to the studio top and you're on your way. A rugged solidly built unit designed for many years of continuous duty. Comes complete with TT -12 turntables, viscose damped ise arms, eight input audio console $845.00 The A-10 Audio Console provides a total of eight high or low level A-50 inputs. Up to date solid state design plus plug -in - PORTABLE STUDIO modular construction. Can be battery operated $375.00 Call, Write or Wire Today %PA RTA ELECTRONIC CORPORATION 6430 FREEPORT BOULEVARD SACRAMENTO 22, CALIFORNIA GA 1-2070 December. 1962 35 www.americanradiohistory.com a bar or base of known length, ar- try. For each zone of 15° of longi- time, 31/2 hours slower than Green- ranged horizontally. The angle sub- tude around the world the time varies wich, and Yukon time, 9 hours slower tended is measured by a transit or by 1 hour; however, where a country than Greenwich. as theodolite accurately as possible, overlaps a zone or more, in order to Theodolite-A theodolite is also a pre- several times. have a uniform national time, its legal cision surveying instrument similar to Sidereal time-Sidereal time is measured time may differ by one-half or less a transit, but has greater accuracy. It by the apparent motion of fixed stars. from the neighboring zone. In Eng- is used principally in geodetic triangu- The sidereral day is the interval be- land, the standard time is the mean lation, and is graduated so it can be tween two successive transits of the local time on the meridian that passes read to the nearest second. first point of Aries over the upper through Greenwich. In the U. S. there Transit-A transit is a precision survey- meridian of any place, and is equal to are four official time standards- ing instrument used for measuring, 23 hours, 56 minutes and 4.09 sec- Eastern, Central, Mountain, and Pa- laying out horizontal and vertical onds of mean solar time. A sidereal cific, corresponding to the mean local angles, and determining differences in day has 24 sidereal hours, each of 60 times of the 75th, 90th, 105th, and elevations and distances. The vernier sidereal minutes with each minute of 120th meridian West or 5, 6, 7, and 8 scales on transits are designed so they 60 sidereal seconds. hours respectively slower than Green- can be read to the nearest 10 seconds. Standard time - Standard time is the wich. In addition to these standards, civil time established by law or by Canada has Atlantic time, 4 hours Traverse-Traverse is the procedure of general usage over a region or coun- slower than Greenwich, Newfoundland surveying a line across a field. Triangulation - Triangulation is also a surveying procedure which utilizes a triangle for determining the lengths of inaccessible lines. Trigonometry is used to determine all the dimensions of the triangle after three parts have been determined by measurement. True solar time-True solar time is de- fined as the interval between two suc- cessive upper transits of the sun. The FM MODULATION expression "apparent day" is used MONITOR synonymously with true solar day. True solar days do not have equal length or duration. The information presented above provides the necessary background for further considerations of an- tenna orientation. Such knowledge FCC TBM-4000 is important to the station engineer Type #3-116 $1495.00 since he, as well as the consulting engineer and surveyor, has a def- inite responsibility in antenna sys- tem establishment. We have already discussed the FCC TYPE APPROVED duties of the civil engineer or sur- veyor, who determines the exact Also Monitors SCA MULTIPLEX geographic coordinates of the an- tenna site. Consulting radio engi- Modulation Crosstalk neers, on the other hand, do not Frequency Injection ..M1111. perform surveying functions and are only responsible for: 1. The spacing (in feet) between FM FREQUENCY MONITOR towers. 2. The center -line of the array in relation to True North. 3. The base elevation for each tower (as determined from observation of a "Quad - sheet"). 4. The accuracy required for triangulation and traverse. FCC TBM-3000 Type m 3-113 $495.00 The first two items have already been described; the last two will be covered next month. The conclud- Write Dept. S or phone 402-342-2753 for complete specifications. ing portion of this article will also discuss actual methods of, and originality by equipment for, observations and McMartin Industries,hze. orientation with Polaris: times, cor- 1612 California Street Omaha, Nebraska rection factors, and time conver- sion; procedures for observation of In Canada, Sold by: Canadian Marconi Comoany, Montreal 16. P. Q. the sun. 36 BROADCAST ENGINEERING www.americanradiohistory.com European Antenna Mfr. Opens in U.S. NEWS OF THE INDUSTRY CO. EL. (Complementi Elettronici, S.P.A. of Milan), manufacturer of broadcasting and communications antennas, has an- M M M ME IMI M IZZ MII M M M M M M M M M IZZ M nounced the opening of its sales offices in the U.S. Although relatively unknown in the United States until recently, the Ampex Sponsors Stereo Program be the same but music will be selected company enjoys an excellent world-wide by the individual stations. Stations broad- reputation and has supplied television "Ampex Stereo Time," a half-hour FM- transmitting antennas to all five conti- stereo musical program, is being spon- casting the series are: KPEN-San Fran- cisco, WVCG - Miami, WDTM - Detroit, nents. The company's U.S. offices, in sored by Ampex Corp. in 10 major mar- Westfield, N. J., will be headed by R. J. kets. The program is being carried three SQXR-New York, WFLN-Philadelphia, WASH -Washington, D. C., KVIL-Dallas, Rainey. CO. EL's entire line of products times weekly by each of 10 FM stations. will be made available, including low KFMU - Los Angeles, WKFM - Chicago, Featuring the first prerecorded Ampex and high band and UHF TV antennas; stereo commercials, program format will and WBCN-Boston. VSB filters, notch diplexers, filterplexers, and harmonic filters; 10 -mc bandwidth FM antennas; rigid transmission line; microwave parabolic antennas, passive re- flectors, and waveguides; parabolic track- G.E. Asks FCC Adopt Stereo TV-Sound Standards ing and radiotelescope antennas; short- General Electric Co. has asked the FCC to adopt standards for compatible wave fixed and rotating high -power log stereophonic sound transmission for television. At the same time, G -E has periodic antennas. proposed a system developed by Robert B. Dome of the Television Receiver Dept. The company says the development program which resulted in its FM -Stereo Stations To Hit 250 proposed TV-Stereo sound system has three main objectives: (1) To develop a compatible system which in no way would degrade the existing monophonic By the end of this year, two hundred and broadcast service; (2) To develop a system which would provide inexpensive fifty FM stations-roughly 25% of those stereo receivers; and (3) To develop a system which would not impose an currently in operation-will be transmit- unreasonable economic burden upon existing broadcast stations. ting FM stereo. This is the prediction of All of the objectives have been accomplished, according to G -E, and in its Harold L. Kassens, chief of the FCC's petition to the FCC, reported that its proposed system has had "limited field Aural Existing Facilities Branch. Mr. testing under actual operating conditions." This testing included operation Kassens said the rate at which conver- under strong co-channel interference which occurred when temperature inver- sion notifications are being received, the sion produced exceptional propagation from a Canadian station operating on number of FM stereocasters could go as the same television channel. These field tests satisfied G -E engineers that their high as 300 before next January 1, and system produced consistently good stereo sound whenever a usable TV picture ultimately FM stereo will replace mono- was being received. phonic FM. Psychological tests, performed to determine reaction to stereo TV sound, While the size of monaural record indicated that it was more pleasant than monaural, the company said, adding, libraries impedes conversion of large "it was a result that might not be unexpected." According to G -E, the separa- stations, Mr. Kassens observed, new sta- tion inherent in stereophonic sound is enhanced by the addition of visual tions do not have this problem and the separation on the TV screen; with the added ability to both see and hear majority of them will be stereo. He also from which side of the orchestra sound is coming, realistic presence reaches said the FCC hopes its proposed rules a peak. Considering the perspective and depth TV-Stereo may lend to tele- revision will provide frequencies needed vision plays, sports events, and the like, it may well be the next major for FM radio to expand as the country improvement in telecasting. grows. The Commission believes, Mr. Kassens stated, that broadcasters now operating marginal AM stations will be A PROFESSIONAL STEREO TONE ARM THAT "THINKS" FOR ITSELF ...designed for people who sometimes don't One moving part, one precision bearing. Nothing delicate to add to your maintenance worries. Change cartridge in seconds. Pre -loaded slide assembly automatically adjusts for lateral and vertical balance, cartridge overhang and output. Viscous damping eliminates audio frequency vibrations, yet offers no resistance to groove motion. GRAY 208-S $49.50 write on company letterhead for complete technical infor- mation, specifications and GRAY AND DEVELOPMENT CO. INC. application data. RESEARCH f Box 12, Elmwood, Conn. Plant: North Mountain Road, Newington, Conn. December, 1962 37 www.americanradiohistory.com encouraged to convert to FM when they realize that the new frequency assign- ment plan will assure them of guar- anteed service areas protected against ATTENTION: interference. OWNERS OF RCA BTF-3B McMartin Moves to New Plant McMartin Industries, Inc., Omaha, Nebr., FM TRANSMITTERS is moving to a modern new plant, accord- ing to Ray McMartin, President. The new location, which increases plant ca- YOUR TRANSMITTER IS CAPABLE pacity by approximately 14,000 sq. ft., will contain the firm's general offices, OF SUPERB FM STEREOPHONIC engineering laboratories for research and TRANSMISSION WITH THE development, and production facilities. The company, founded in 1956, manu- factures audio amplifiers for the back- ground music industry, and through a national sales force of 54 men, provides MOSELEY Model SCG-3 a large percentage of the multiplex re- ceivers used by background music oper- FM STEREO GENERATOR ators to service individual subscribers. The firm also produces electronic equip- PROVEN IN ACTUAL OPERATION ment for RCA and Collins Radio. Sound Corp. Opens New Plant WRITE TODAY FOR COMPLETE TECHNICAL, Sound Corporation of America, manu- CONVERSION, TYPE & ACCEPTANCE PRICE DETAILS facturers of "Channel-Matic" background SATISFACTION GUARANTEED music systems, tape cartridges, and other related play-back equipment has consoli- MOSELEY ASSOCIATES, INC. dated all administrative, R & D and pro- P.O. Box 3192 4416 Hollister Ave. duction facilities at 45 New Street, Wor- Telephone 967-1469 cester, Mass. According to Richard P. SANTA BARBARA, CALIFORNIA Ellison, President of the firm, the Wor- cester plant not only provides additional R & D facilities presently required for their new production line, but will also enable the company to meet future pro- duction demands. for your tower ROHN requirements Electrical Engineering Exposition check SYSTEMS Efforts are underway to assure the Elec- trical Engineering Exposition of the largest gathering of leading electrical A complete tower CONTINENTAL'S engineers and management executives erection service ever assembled in any one place. Litera- TYPE MR1C ture and informative has these material, stressing that the value of attending, have been placed special advantages: MONITOR RECEIVER before more than 200,000 electrical - electronic engineers and management DEPENDABILITY Monitors transmitter executives by the American Institute of Electrical Engineers, sponsors of the Ex- operation at RELIABILITY studio location position. The Electrical Engineering Exposition will be held January 28-31 V COMPLETE Indicates relative field in the New York Coliseum as part of ENGINEERING intensity at pickup point the 51st Winter General Meeting of the AIEE. The Reber -Friel Company, man- COAST TO COAST agement firm in charge of the event, Has audio monitoring SERVICE reports that nearly 50% of the available channel exhibit space has already been reserved. Be sure to obtain price quota- tions and engineering assist- ance for your complete tower Gives warning lamp for Free Hunting and Fishing Tape Series needs from America's foremost carrier, buzzer alarm for tower erection service. Authentic hunting and fishing stories are loss of carrier the subjects of two radio tape series now being offered by the Utica Duxbak Corp. write for details today and Horrocks-Ibbotson Co. Each series contains 13 scripts of 15 minutes dura- tion, and are available on a free -of- charge, exclusive -market loan basis to radio stations. Each script contains breaks MANUFACTURING COMPANY for local sponsors, one complete and ROHN SYSTEMS, INC. BOX 17040 DALLAS 17, TEXAS authentic story, and a question -and - 6718 W. Plank Road Peoria, Illinois Subsidiary of Ling-Temco-Vought, Inc answer section. 38 BROADCAST ENGINEERING www.americanradiohistory.com NEW PRODUCTS iM M M M ® M M M M M M ien M M M v M e a when acoustical conditions vary widely . . . Constant -Output Amplifier Consisting basically of a two -stage push-pull circuit, this new constant -output amplifier by Amplifier Corp. of America, New York, N. Y., provides optimum limiting action with minimum distortion. The input may be connected either directly to a balanced 600 -ohm line or it may be bridged across an unbalanced line without upsetting the impedance. The gain control feature automatically keeps input changes as great as 40 db within ±2 db of peak modulation levels, eliminating the element of human error. Complete technical specifications and prices of the Model 740-C-1 are available from the manufacturer. . . . equalize with the factured by Allen Electronic Corp., Palo Telefunken M 251 E Alto, California. It can test VTR signal systems from video input to video out- Condenser Microphone put; provide an output for simultaneous display of individual head and elec- Pick your pattern with a flick of the switch evaluate combined tronics performance; Cardiod, Omnidirectional or Bi-Direc- or individual performance of playback tionai. The Telefunken M 251 E gives you preamplifiers, switcher, modulator, and three patterns, gives you other impor- demodulator; and aid in pinpointing all too: Flat frequency re- noise sources. tant advantages sponse with smooth roll off on both ends, The unit allows all four head channels VTR Sweep Generator high sensitivity, Telefunken design and to be quickly matched to eliminate band- A new generator designed for alignment construction throughout ing, simplifies the record -head -current and testing of video tape recorders has make the M 251 truly been announced by Visual Electronics optimization procedure, and provides a a "sound investment". Corp. Called the Video Sweep Gener- standard test signal that can be pre- leader. The sweep ator Model 960 -GM, the unit is manu- recorded on tape Whenever true recording excellence is essential, your finest choice is a K PROFESSIONAL TURNTABLES professional microphone by Telefunken. There's one for every applica- offer you more tion - also a complete QUALITY range of world-renowned studio equipment. Write CONTINUOUS PERFORMANCE wy today for further infor- SIMPLICITY mation and technical data to: Quality all the way with QRK. Full speed range -33, 45, 78. Built rugged with jewel pre- Priced from cision. Plays 45's without adapters. Rocket acceleration $110. to $235. idler maintains constant speed re- - EZ queing. Single Send for normal wear. gardless of detailed folder! TELEFUNKEN American Elite, Inc., Dept. 25,48-50 34th St. Western Distributor Phone CY 9-4692 Long Island City, N. Y. 'I'M'SCO Electronics Mfg. 1406 Clovis Ave. - Clovis, Calif. Telefunken Sales & Service Headquarters for over a decade. December, 1962 39 www.americanradiohistory.com generator, which sweeps 0 -IO me at a In January-A Special on rate of either 60 or 960 cps, can also be used for conventional TV broadcast - equipment alignment. In the 960 -cps mode, it can be locked to the drum Antenna Systems servo of a VTR to give a 0-10 me sweep of each head pass to permit viewing a simultaneous display of all four head characteristics on a standard waveform monitor or oscilloscope. Markers may be individually switched in or out at frequencies of 1-10 mcs. The 960 -GM has an internal gated mixer for adding sync and blanking for operation in a system with clamp amplifiers. With or without the gated mixer, the instrument is available for 525 and 625 line sys- tems; other TV standards are available on request. a..,..w.a-.Ia. s -a ;s4r»-fiyg e m Beeeeeee Solid -State Video Amplifier A transistorized video distribution am- plifier, Model VA -1, has been introduced by CBS Laboratories, Stamford, Conn. Designed specifically for television broad- casting, military, and industrial video systems, the new solid-state TECHNIQUES package con- FOR USING RG -17/U COAX tains eight plug-in amplifiers (also sold Suggestions for measurements and techniques to keep line losses to a minimum. individually) and two power supplies. Capacity is 24 outputs, at approximately LOCATING DIRECTIONAL ANTENNA SYSTEMS $100 per output, in a package occupying Part Two. Valuable pointers for all station engineers concerned with planning 71/4" in a standard rack. Utilizing large directional antenna systems. amounts of feedback, the unit has pro- visions for presetting individual ampli- REMOTE PICKUP ANTENNA SYSTEMS fier gains at 0, 3, 6 or 9 db. The pack- Factors to consider in the design and installation of remote broadcast pickup age is powered by a dual supply ar- antennas. rangement in which a standby power supply takes over automatically if the EFFECTS OF VSWR ON STEREO SEPARATION prime supply power fails. Investigation of transmitting antenna standing -wave ratio and stereo separation. New I -kw AM Transmitter THE "HOT" WATER TANK AT WJIL A new 1,000 -watt AM broadcast trans- A system for eliminating re -radiating objects which cause antenna pattern distortion. mitter, Model BC -1G, has been intro- duced by Gates Radio Co., subsidiary of MECHANICAL ASPECTS OF ANTENNA TOWERS Harris-Intertype Corp. The transmitter is available with either silicon or tube Considerations which affect the stability and safety of antenna towers. rectifiers. In the solid-state model, the high-voltage power supply utilizes 60 TECHNICAL TALKS silicon diodes, each rated at one full Series- and shunt -fed antennas - faced with a choice, here are the factors to amp. The combination of a cathode - weigh in making your decision. follower audio driver, low leakage re- ... PLUS, of course, the ever -popular ENGINEERS' EXCHANGE column, containing actance in the modulation transformer, numerous suggestions and ideas for improving broadcast operations. and modulating the RF driver as well as the power amplifier, results in low inter - modulation distortion. Us this handy order form to have BROADCAST ENGINEERING mailed to you every month. HOWARD W. & INC., SAMS CO., 4300 W. 62nd St., Indianapolis 6, Indiana Line Voltage Regulator Please enter my subscription to BROADCAST ENGINEERING for the subscription period indicated. Availability of the Model VR -6 voltage regulator has been annnounced by Flow 3 years $13.00 2 years $10.00 1 year $6.00 Corp., Cambridge, Mass. The device is Check or money order enclosed Please bill me a servo-controlled motor -driven variable Please check BOTH Your business and occupation autotransformer designed particularly to Name E AM Radio Station E Owner, Manager, maintain line voltage at 115 ±2 volts E FM Radio Station Officer with inputs from 80-115 volts VC, 60 E Television Station E Engineer, Technician Firm E Network cps. The compact unit measures 15" by E Consulting Engineer Other 8", can handle loads up to 30 amps, and Address E Manufacturer or Distributor is easily mounted due to its smooth, non - E Recording Studio protruding surfaces. The VR -6 is City Zone State E Government Agency, outer Library, School 1262 priced at $275, f.o.b. Cambridge. 40 BROADCAST ENGINEERING www.americanradiohistory.com There's a NEW JAMPRO BATWING ANTENNAS FAIRCHILD FOR VHF TELEVISION CONAX on top of the Empire State Building! WNEW-TV Channel 5 Wide -Track Magnetic Recorder in New York uses the FAIRCHILD CONAX to The first wide -track magnetic tape mas- maintain high average audio ter recorder was introduced by Ampex levels despite pre -emphasis Corp. at the recent Audio Engineering problems. The CONAX is silently Society convention. The new three -chan- at work minimizing problems cre- nel Model 330-3 uses 1" tape, specially - ated by sibilants, finger snapping, designed heads, and modified Model 300 the shrill sounds of children, the transport and electronics to provide im- rattling of dishes, muted trumpets proved signal-to-noise ratio, frequency and cymbals, which are all part of response, distortion and flutter over WNEW-TV's program schedule. No previous tape and 35 -mm magnetic -film more reduction of apparent loud- recorders. Major modifications include: ness because of these high frequency two heavier torque motors for optimum problems. performance with 1" tape on 14" reels CONAX has been engineered by FAIR- at 15 and 30 ips speeds; a fluid -damped CHILD to cope with the problem of flywheel which reduces flutter and wow distortion produced in recording and (0.05 rms max.); and an improved re- broadcasting by excessive, instanta- cording amplifier power output with re- neous high frequency peaks. The FAIR- duced distortion. The recorder employs CHILD CONAX "previews" program wide -track and fixed -azimuth heads with material in emphasized form for effi- three 250 -mil tracks on 335 -mil centers. cient high frequency control. The Priced at $7,500 unmounted and $7,875 device is based on the integrating console -mounted, it is available on a properties of the human ear. The special order basis. CONAX action is inaudible and instan- taneous - 1 40,000ths of a second. . CONAX produces increased signal f levels in recording and FM broad- cast. - JAT2/5L CHANNEL 5 CONAX reduces distortion in tape recording and tape duplication. IMPROVED O r ia + 111111 CONAX minimizes channel cross- talk in stereo broadcasting. INTERBAY CABLE AND if@ +.. CONAX eliminates high frequency END TERMINATIONS, "splatter" between stereo channels LOW VSWR SCA Subcarrier Generator and SCA channel. Why not let the FAIRCHILD CONAX Your choice of input power ratings. Moseley Associates, Inc., Santa Barbara. help you maintain high average audio newest subcarrier H series for 35 and 50 KW, L series Cal., announces their levels. generator, Model SCG-4, for SCA multi- with 21/2 KW per bay. plex operation. The unit is designed to FAIRCHILD RECORDING EQUIP. CORP. operate on any frequency in the SCA 10-40 45th Avenue, Long Island City 1, N. Y. Widest choice of VHF batwing an- spectrum and meets FCC specifications MAIL THIS COUPON FOR COMPLETE DATA tennas are now available only from for multiplex and stereo operation. Mounted on an 83/4" panel, all tubes, FAIRCHILD RECORDING EQUIPMENT CORP. JAMPRO. One through six bays for plug-in relays and capacitors, and adjust- 10-40 45th Avenue channels 2-6 and one, two, four, six, ments are available from the front. Heat Long Island City 1, N. Y. eight and twelve bays for channels dissipating shields are used for reliability Dear Sir: and extended tube life. Please send me complete information on the 7-13. Fairchild Conax Write for Catalog Name New Transmitting Tube Manual JAMPRO ANTENNA CO. Firm Name 7500 - 14TH AVENUE The new RCA Transmitting -Tube Man- ual includes the latest information on Address SACRAMENTO 20, CALIFORNIA power tubes and their applications, as City Zone State well as the new "cermolox" family of December, 1962 4I www.americanradiohistory.com Advertisers' Index ceramic -metal types. The 320 -page hand- Vane A. Jones is a ready source of book, just published by the RCA Elec- information UM on any TV as well as any r---- -®-- tron Tube Division, has been revised AM or FM station in the U.S. and its American Elite, Inc. 39 and updated to contain new single -side - possessions, Canada, Cuba, Mexico, and Amperex Electronic Corp 19 band ratings, a discussion of linear RF the West Indies. Contains over 7,500 sta- Ampex Corp. 19 amplifiers, and calculation of operating tion listings, including 5,000 AM and conditions for 2 -tone modulation. Maxi- 1,500 FM radio stations by city, state, Battison, John H. & Assoc. 42 mum ratings, typical operating values, and frequency; and nearly 1,000 VHF Bauer Electronics Corp. 31 curves, and characteristics are given for and UHF TV stations. Also included are Belden Mfg. Co. 43 more than 180 types of transmitting the 14 U.S. maps-one for each of the and related rectifier in 12 VHF Broadcast Electronics, Inc. 24 tubes the technical channels, a UHF TV map, and data section. The popular circuit section an FM station map. Price is $1.95. CO.EL. Company 7 contains typical transmitting circuits. Available Conrac Div., Giannini Controls Corp. 33 from RCA distributors or di- rectly from the company, price is $1.00. Continental Electronics Mfg. Co. ... 38 Cousino Electronics Corp 4 Classified Electro -Voice, Inc. 34 Advertising rates in the Classified Sec- Fairchild Recording Equipment Corp. 41 tion are ten cents per word. Minimum charge is $2.00. Blind box number is 50 cents extra. Check or money order must Gates Radio Co. 5 be enclosed with ad. Gray Research & Development The classified columns are not open to Co., Inc. the advertising of any broadcast equip- 37 ment or supplies regularly produced by manufacturers unless the equipment is IERC Div., International Electronic used and no longer owned by the manu- Research Corp. 6 facturer. Display advertising must be purchased in such cases. International Nuclear Corp. 25 ITA Electronics Corp. 2 EQUIPMENT FOR SALE James, Vir. N. 42 Jampro Antenna Co. 41 Transmission line, styroflex, heliax, rigid Kudelski, S. 29 New Tube Tester with hardware and fittings. New at sur- A new tube tester, Model 539C, by plus prices. Write for stock list. Sierra Western Electric Cable Co., 1401 Middle McMartin Industries, Inc. 36 Hickok Electrical Instrument Co., Cleve- Harbor Road, Oakland 20, California. Moseley Associates 38 land, will test VR Tubes, low power 6-61 tf thyratrons, Radio Corp. "4 -digit" industrial types and of America all the newest Commercial Crystals and new or replace- Electronics Products Div. 8-9 tubes, including compac- trons, Novars, Nuvistors ment crystals for RCA Gates, W. E., Rohn Systems, Inc. and 10 -pin Bliley and J -K holders; regrinding, re- 38 types. This industrial and laboratory tube pair, etc. BC -604 crystals. Also A. M. Russco Electronics Mfg. 39 monitor service. Nationwide unsolicited tester checks tubes to handbook speci- testimonials praise our products and fast Schafer fications, and evaluates voltage -regulator service. Eidson Electronic Company, Box Electronics 20 31, Temple, Texas. 9-61 tf Sparta Electronic Corp. 35 tubes under actual operating conditions. The instrument has provision for moni- Stancil-Hoffman 42 GOVERNMENT SURPLUS, NEW 10 CM. toring of plate current, through panel WEATHER Superscope, Inc. 21 RADAR SYSTEM-Raytheon, terminals, facilitating matching or bal- 275 KW peak output S band. Rotating Sylvania Electric Products, Inc 3 yoke P.P.I. Weather Band 4, 20 and 80 ancing of tubes. Tests may be conducted mi. range. Price $975 complete. Has under fixed or self -bias conditions, and picked up clouds at 50 mi. Wt. 488 lbs. Visual Electronics Corp. 28 Radio Research Inst. Co., 550 5th Ave., Victor Records Div. 27 nonstandard tests are facilitated by the New York, New York. 5-62 8t panel terminals giving access to grid. plate, cathode, and heater circuits. The Will buy or trade used tape and disc re- unit is available from Hickok distributors cording equipment-Ampex, Concertone, Professional Services Magnecord, Presto, etc. Audio equipment and carries a suggested user price of for sale. Boynton Studio, 295 Main St., $485.00. Tuckahoe, N. Y. 10-62 6t I MI Mil e se MI 1311 Sound Reproduction Book Collins Tape cartridge machines $275 ea. VIR N. JAMES "Reproduction of Sound," by Edgar Vill- Gates Sta -Level $150. Concertone Stereo CONSULTING RADIO Recorder $375. Excellent condition. Write ENGINEERS chur, is announced by its publisher, -Box 125, Lafayette Hill, Pa. 11-62 2t Applications and Field Engineering 232 S. Jasmine St. Acoustic Research, Inc., Cambridge, Phone: (Area Code 303) 333-5562 Mass. This 93 -page book is a nonmathe- POSITION WANTED: Will receive my DENVER 22. COLORADO matical analysis of the nature of sound BS degree in Speech, with Area Concen- Member AFCCE tration in Radio and Minor in Psychology, and of how reproducing components Jan. 63. Have 3 years experience announc- work. The illustrated book may be used ing and producing news, classical and popular music, sports, and commercials. as a general survey of principles, or as Can run my own board. Seek permanent SYNCHRONOUS MAGNETIC FILM a pre -engineering text and introduction. position on Broadcasting Staff-will re- RECORDER DUCER locate for right opening. MAGNETICRECORDERSTAPEEO The first few chapters deal with the BROADCAST ENGINEERING Box 1162-1 NEW-THE portable MINITAPE syn fundamental nature of sound and the chronous 13 lb., battery operated magnetic tape recorder for field re- standards applied to high-fidelity repro- 10 -inch Soundcraft blank recording discs, cording. ducing systems. A brief discussion of package of 25, $9.00, postpaid; cash, THE STANCIL-HOFFMAN CORP. check or M.O. Studio, 6110 Santa Monica 845 N. Highland, Hollywood 38, Calif. recording, with emphasis on stereo, is Blvd., Hollywood 38, California. 12-62 2t Dept. B HO 4.7461 followed by a treatment of each of the reproducing elements in turn: pickups and needles, preamplifiers and amplifier, MISCELLANEOUS JOHN H. BATTISON & ASSOCIATES speaker systems, and the listening CONSULTING RADIO ENGINEERS room. Available directly from Acoustic Re- Specializing in AM -FM-TV Applications ENGINEERING And Art Degrees earned and measurements. search, price is $2.00, postpaid. through home study. Electronics, Me- 934-5 Munsey Building chanical, Liberal Arts. When writing spe- 1329 E. St., N.W. Washington cify course desired. Pacific International 4, D. C. Broadcast Station Guide College of Arts & Sciences, primarily a DI 7-2330 The new Howard W. Sams "North correspondence school. Resident classes Established 1954 also available. 5719-W Santa Monica American Radio-TV Station Guide," by Blvd., Hollywood 38, California. 8-62 6t 42 EROADCAST ENGINEERING www.americanradiohistory.com This is KTRK-TV's new broadcasting station in Houston, Texas. The exclusive use of Belden camera, audio, and control cables by this ABC affiliate helps assure KIRK of continuous, highly efficient programing. Looking over part of this 155,000 -foot Belden wire and cable installation are Byron Turner, Salesman, Sterling Electronics (left), Jess Mitchell, KTRK Engineer (center), and Bill Donahoe, Belden Territory Salesman. They are standing in front of a Belden wired control panel in one of the many KIRK studios. All of the wire and cable for this installation was placed through Sterling Electronics-one of Beiden's Houston distributors. 155,000 ft of Belden Audio, Camera, and Control Cable helps keep KTRK-TV on the air For all TV and radio broadcasting, recording studios, remote control cir- cuits, and similar applications, Belden manufactures the most complete line of application engineered wire and cable. Call your Belden electronics distributor for complete specifications. WIREMAKER FOR INDUSTRY SINCE 1902.- CNICAOO Power supply cords co d sets and portable cordage electrical hosseho'd cords magnet wire lead wire 8T02 www.americanradiohistory.com Can a lobt conversion in your transmitter result i major improïements? YC3 ... and here's why: Amperéx transmitting tubes-more reliable than the tubes If your transmitter ...and, at present, ... these Amperex in your transmitter at present-give you these improvements is one of those it uses any of the tubes give you ma- in 1KW to 25KW AM, FM and TV transmitters: longer life listed below: following tubes: jor improvements: without premature failure worries and lower dollar -per -hour 1KW FM 7C26 5759/501-R operating cost. 3KW FM 7D21 6076 5KW FM or TV '8D21 6076 The proof? For the past 3 years, Amperex has successfully 10KW FM 5518 SD505 assisted with conversions in broadcasting stations all over 5-25KW AM or FM 5762/7C24 or 5762A 7459 the country-and we'll be glad to tell you where and how. 5-25KW TV 5762/7C24 or 5762A 7900 For complete information, write to Amperex-or call your local Interested? Amperex has not only the tubes but the acces- Amperex distributor. Amperex Electronic Corporation, Power sories and all the applications engineering assistance neces- Tube Department, 230 Duffy Avenue, Hicksville, L. I., N. Y. sary for your conversion. In Canada: Philips Electron Devices Ltd., 116 Vanderhoof Ave., Toronto 17, Ont. -3 % -eJ/. _ www.americanradiohistory.com