4/70 - americanradiohistory.comamericanradiohistory.com/Archive-Catalogs/RCA/RCA-AM-FM... ·...

*,/, /4/70/702t/

TransmittingAM I FMEquipment

Catalog Supplement

Broadcast Catalog SupplementTO KEEP YOUR CATALOG UP TO DATE, this sup-plement contains material which either extends orsupersedes that now existing in your AM- or FM -Radio Catalog. A new AM/FM catalog is in prep-aration for distribution later in the year. Until then,the combination of this supplement and your cataloggives you the complete product line.

ContentsCatalog

AM Transmitters B.6001 toB.6050

FM Transmitters B.6500 toB.6535

FM Exciter B.6556

Transmitter Monitors 8.6822 toB.6830

FM Transmitter Dummy Loads B.4518

FM Antenna Equipment 8.6759 toB.6765

RCA 1Commercial Electronic Systems Camden, New Jersey 08102, U.S.A.

RCABroadcastSales Offices

Atlanta, Ga. 3032914 Executive Park Dr. N.E.

404-634-6131

Austin, Texas 787678330 Burnet Rd.Northwest Office Park Bldg.Suite 134 512-453-8233

512-451-2500

Birmingham, Ala. 35223Office Park Bldg. #10Office Park Circle 205-871-1155

Boston Area360 First Ave.Needham Heights, Mass. 02194

617-444-7200

Burbank, Calif. 915052700 W. Olive Ave. 213-849-6741

Camden, N.J. 08102Front & Cooper Sts. 609-963-8000

Charlotte, N.C. 28204330 Charlottetown Center

704-333-3996

Chicago, III. 60606120 S. Riverside PlazaGateway 11 Bldg.Suite 1400 312-782-0700

OUTSIDE THE UNITED STATES

Buenos Aires, ArgentinaRCA International Ltd.Calle Paroissien 3960

North Ryde, N.S.W., AustrialiaRCA Limited11 Khartoum Road

Middlesex, EnglandRCA LimitedSunbury -on -Thames

Cincinnati, Ohio 452318234 Winton Rd. 513-522-8810

Cleveland, Ohio 441151600 Keith Bldg. 216-579-0880

Columbus, Ohio 43221100 Henderson Rd. 614-451-1127

Dallas, Texas 75235210-C Court TerraceExchange Park, N. 214-351-5361

Denver, Colo. 802112785 N. Speer Blvd.Suite 346 303-433-8841

Detroit Area20830 Rutland Ave.Southfield, Michigan 48076

313-357-0080

Indianapolis, Ind. 462052511 E. 46th St.Bldg. 1, Suite Q 317-546-8571

Kansas City Area5750 W. 95th St.Suite 111Overland Park, Kansas 66207

913-642-3185

Memphis, Tenn. 381174990 Poplar Ave.Suite 209

Hong KongRCA International Ltd.1927 Prince's BuildingChater Road

901-683-6371

Mexico 6, D.F., MexicoRCA CESDReforma 382-Room 201

1227 Geneva, SwitzerlandRCA International Marketing, S.A.2-4 Rue du Lievre

Minneapolis, Minn. 554164522 Excelsior Blvd. 612-922-3303

New York, N.Y. 100361133 Ave. of the Americas5th Floor 212-586-3000

Orlando, Fla. 328105330 Diplomat CircleSuite 30 305-644-9135

San Francisco, Calif. 94104343 Sansome St.7th Floor 415-956-4818

Seattle, Wash. 981342246 First Ave., S. 206-622-8350

St. Louis, Mo. 631057733 Forsyth Blvd. 314-862-3660

Washington, D.C. Area1901 N. Moore St.Arlington, Virginia 22209

703-558-4212

West Palm Beach, Fla. 334033900 RCA Blvd.Palm Beach Gardens 305-844-7351

Montreal, Quebec, CanadaRCA Victor Company Ltd.1001 Lenoir Street

Vancouver, B.C., Canada2876 Rupert Street

Winnipeg, Man., Canada2070 Notre Dame Ave.St. James 21

Toronto, Ont., Canada1450 Castlefield Ave.

catalog B.6001

RC/1 1 KW AM Broadcast Transmitter, Type BTA-1R3

Excellent frequency response

Low distortion

Circuit breaker overload protection

Low operating costs

3T3

BTA-1R3 Transmitter with front door removedshowing accessibi ity of tubes and compo-nents. cower amplifier and Modulator tubesare shown on top chassis; below is exciterchassis. All normal operating controls areon two side panels.

Rear view of BTA-1R3, with rear panels re-moved, showing vertical construction andaccessibility of component parts.

DescriptionThe RCA Type BTA-1R3, 1 -kilowatt

AM Broadcast Transmitter is designedfor reliability, outstanding fidelity, andeconomical operation. It provides a highquality amplitude modulated signal at anyfrequency in the 535 to 1620 kilohertzband and is capable of producing a max-imum of 1100 Watts.

Highly perfected audio circuits to-- gether with a large, high -quality trans-

former and reactor provide tremendousmodulation capability and unusuallyHigh Fidelity sound. Stable, long -lifetubes and avalanche diode rectifiers havebeen used throughout the transmitter.Circuit breakers-not fuses-provide com-plete overload protection.

Provision for remote control and sim-plified power cutback are reflected inthe BTA-1R3 design. Front panel or re-mote control selection of any two powerlevels of 1000, 500 or 250 Watts is avail-able. No unnecessarily complicated cir-cuitry or superfluous parts have beenincluded and all components are easilyaccessible for maintenance and inspection.The transmitter is designed for 208 or240 Volt operation.

Functional DesignImproved functional design includes

RCA's new color combination. Squareconstruction permits locating the trans-mitter against the wall, or it can be in-stalled against other equipment. Thevertical construction makes it accessiblefrom both front and rear for ease ofmaintenance. A single front panel tuningcontrol provides simplified operation. Re-mote control provisions permit unat-tended operation of the transmitter.

- Simplified Power CutbackThe BTA-1R3 easily fits into opera-

tions where power reduction at night isrequired. For "day -night" operation anoptional Power Cutback Kit may be in-corporated in the transmitter. By pressing- a switch on the front or at a remotepanel, the transmitter can be cut backin power to either 500 or 250 Watts. Ef-ficient operation at the low power levelsis achieved by reducing the high voltageby primary taps on the plate transformer.

Complete Accessibility

T The entire transmitter is housed in asingle steel cabinet that is mounted on asturdy welded steel base. Control com-ponents are conveniently located on the

control panels on both sides of the frontdoor and all meters are at eye level.Easy access is provided by a hinged frontdoor and two interlocked removablepanels. Most BTA-1R3 components aremounted on a vertical center chassis.Tubes and overload relays are mountedon the front and the other componentsare mounted on the rear. Larger powercomponents are mounted on the base.

Solid State Power SuppliesThree power supplies are used: a low

voltage supply for plate and screen volt-ages of all low voltage tubes, a bias sup-ply for the modulator tubes, and a highvoltage supply for the modulator andpower amplifier tubes. All power suppliesuse avalanche diodes which results inlower power drain, cooler operation andmore reliable performance.

Power RequirementsThe transmitter operates from a 208-

240 Volt, 60 Hz single phase powersource for the main power. In addition,the crystal heaters require an additional115 Volt power input. The transmittercan be modified for operation on 50 HzAC current if desired.

Switchable CrystalsThe BTA-1R3 offers the customer a

choice of tube type or solid-state exciter -buffer. Both employ two switchableTVM-130B temperature controlled cry-stal units. These units maintain the fre-quency constant to within plus or minusfive Hz. Selection of the desired crystal isby means of front panel switches andlatching relays. The oscillator employs abroadband circuit with no adjustments.

Simple, Straightforward CircuitryThe buffer feeds a single 6146A driver

tube which in turn feeds the power am-plifier which consists of two 4-400Atubes connected in parallel. Tetrodes havebeen utilized throughout the RF sectionof the transmitter reducing the requiredstages and the power consumption. Tet-rodes also eliminate the need of neutrali-zation.

The modulator comprises two 2E26tubes in push-pull resistance coupled totwo 4-400A modulator tubes. The modu-lator tubes operate as a class A131 ampli-fier without grid current which results inan overall distortion of less than 2 per-cent up to 10,000 Hz.

X TA L BUFFER IPA P. A.OSC.6AK5' 5763 6I46A 2-4-400A

1ST AF

2-2E26MOD.

2-4-400 A

L V. BIAS H.V.

RECT. RECT. RECT.

SILICON SILICON SILICON Simplified block diagramof BTA-1R3 AM Transmitter.

*Tube or solid-state Oscillatcr-Buffer can be specified..

SpecificationsPerformanceAF Input Impedance 150/600 Oh ms

AF Input Level (100% modulation) +10 ±2 dBmAF Response:

50-7500 Hz ±1 dB30-10,000 Hz ±1.5 dB30-15,000 Hz ±3 dB

AF Distortion (95% modulation):50-10,000 Hz 2%50-12,000 Hz 3%

Noise (below 100% modulation) 60 dB

Frequency Range 535-1620 kHz

Frequency Stability ±5 HzType of Output Single ended

Carrier Shift (0-100% modulation) 3%

Output Impedance 40-250 Ohms

ElectricalRF Voltage (for frequency monitoring) 10 V RMS 75 Ohms

RF Voltage (for modulation monitoring) 10 V RMS 75 Ohms

Power Output (nominal) 1000 Watts

Power Output Capability 1100 Watts

Power Supply 208/240 Volts

Line Frequency 60 Hz

Phase 1

Power Consumption:(0% modulation) 2900 Watts (approx.)(100% modulation) 3900 Watts (approx.)(average program modulation) 3200 Watts (approx.)

Power Factor 90%

Permissible combined line voltage variationand regulation ±5%

Crystal Heater Power Supply 115 Volts 50/60 Hz

Ordering Information

Tube Complement

1 6AK5*1 5763*1 6146A2 2E262 4-400A2 4-400A

Crystal OscillatorBufferIntermediate Power AmplifierAudio Frequency AmplifierModulatorPower Amplifier

MechanicalHeight 84" (213.4 cm)

Width 34" (86.4 cm)

Depth 321/2" (82.6 cm) (less door handle)

Weight (net) 1700 pounds (772 kg) (approx.)

Altitude Range 0-5000 ft. (0-1524 m)

Ambient Operating Temperature:(min.) -20°C (-4°F)(max.) +45°C (113°F)

AccessoriesOperating Spare Tube Kit MI -27696-A

Recommended Minimum Spare Tube Kit MI -27695-A

Type BTR-11B Remote Control System ES -34280

Type BW-11A Frequency Monitor(Specify frequency) ES -34042

Type BW-66F Frequency Monitor M I -30066-B

Power Max (Negative Peak Limiter) MI -34654

RF Ammeters MI -7157-F Series

Ammeter Mounting Panel MI -34656

Remote RF Pickup Unit (less meter) MI -27966-B

Remote Antenna Meter MI -27644 Series

Automatic Logging Equipment On ApplicationPower Cutback Kit MI -34079

Remote Power Adapt Kit MI -34080

Oscillator -Buffer (Tube Type) MI -27632-A

Oscillator -Buffer (Solid -State) MI -27592

Type BTA-1R3 1000 -Watt AM Broadcast Transmittercomplete ES -27238-D*

(*Ordering information should specify tube or solid-state type OscillatorBuffer.)

Commercial Electronic Systems Division BroadcastFront and Cooper Streets, Camden, New Jersey, U.S.A. 08102 Equipment

catalog B.6007

RCA 5-10 KW AM Broadcast Transmitter, Type BTA-5U2/10U2

Outstanding sound High reliability

Solid state oscillator and buffer

High efficiency circuits Great overall economy

High Efficiency 5/10 Kilowatt Transmitter

Only TwoTuning Controls

Built-in RemoteControl Provisions

DependableSemi -ConductorPower Supply

CompletelyAir Cooled

HighEfficiencyCathode

and PlateResonators

Self-contained 5 -kWPlate Transformer

5/10 KW AM Broadcast Transmitter, Type BTA-5U2/10U2The BTA-10U2 is a 10 kW amplitude mod-

ulated, high fidelity, broadcast transmitter foroperation in the standard band between 535and 1620 kHz. The new model incorporatesRCA's plug-in solid state Oscillator -Buffer,MI -27592 with two switchable, tempera ture-controlled crystal positions.

The RCA BTA-5U2 AM Broadcast Trans-mitter is the fully converted deluxe BTA-10U2 with a second 5762 Amplifier tuberemoved to provide 5 kW output. Both trans-mitters are outstanding in appearance andreliability, and meet requirements of the FCCand EIA.

The BTA-5U2/10U2 operates from a 208/240 Volt, 50/60 Hz, three-phase power sourcefor the main power. The crystal heaters re-

quire an additional 115 -Volt 50/60 Hz singlephase AC power input. Both transmitters ex-ceed nominal power output rating to compen-sate for losses in the antenna tuning equip-ment.

The spacious cabinet of the BTA.-5U2Transmitter permits internal mounting of the5 kW plate transformer. There are provisionsfor easy conversion to higher power at a laterdate. The transmitter allows simplified powerchange to 1 kW or 500 Watts, if desired, byinstalling an optional Power Cutback Kit,MI -34646-A. Similarly, the BTA-10U2 can beoperated at 5 kW, or at 1 kW. The BTA-5U2/10U2 is provided with an oil -filled modula-tion transformer for increased reliability.

DescriptionThe BTA-5U2/10U2 is an air-cooled

transmitter with numerous design im-provements, including an important de-velopment in Class C amplifier design.The new high efficiency, plate modulatedpower amplifier permits one or two long -life 5762 tubes to deliver the nominal 5or 10 kW with 5.5 or 10.6 kW power out-put capability. The plate efficiency ap-

- preciably exceeds that of a conventionalClass C amplifier. As a result, consider-able power savings can be realized. Re-ferring to the simplified schematic, thecircuit arrangement is very similar to aconventional Class C amplifier, except forthe presence of two high efficiency reso-nators. The amplifier is stable and easy toadjust. The high -voltage, low -voltage andbias supplies employ silicon rectifiers- throughout.

Other new design techniques of thetransmitter provide simplified tuning, in-

_ creased safety, longer tube life and im-proved performance. After initial adjust-

_ ments, the transmitter can be tuned fromthe front panel. This is accomplished byonly two controls. Provisions for manualox remote control operation are incorpo-- rated in the transmitter. For safety, alldoors and panels are interlocked and- grounding switches protect operating per-sonnel. The transmitter is air-cooled by- a single blower housed in the centercabinet.

Improved Mechanical DesignThe transmitter is housed in three

attractively styled cabinets made of ano-dized aluminized steel to provide im-proved magnetic and electrostaticshielding. The left cabinet, or cubicle,contains the Transmitter Driver. Thecenter cabinet houses the Modulator andHigh Voltage Rectifier, and the Blower.In the right hand cabinet is located thePower Amplifier, and the 5 -kW PlateTransformer. The plate transformer ofthe BTA-10U2 is an external unit whichcan be mounted near the cabinets.

Accessible VerticalPanel Construction

Each cabinet consists of end panelswith wrap -around front edges formed toprovide control panels, mounted on asturdy, welded steel base. Vertical centerchassis are fastened between the endpanels to form a basic "H" cross section.Reach -in accessibility to transmitter com-ponents is afforded by hinged front doorslocated between the control panels. Rearaccess to each cabinet is provided bya hinged, interlocked door. Control com-ponents are conveniently located on thepanels on both sides of the front doorswhere all meters are situated at eye level.

The matched cabinets are designed tocombine an attractive appearance withthe utmost in utility. Vertical construc-

tion permits easier maintenance andservice. It also permits installation of thetransmitter against a side wall, or allowsother equipment to be placed on eitherside of the cabinet. The front doors ofthe transmitter give immediate access tothe front of the vertical panels on whichcircuit components such as tubes andoverload relays are mounted. Remainingsmall components are mounted on therear of these chassis, while the largerpower components are situated in thebase of the cabinet.

Efficient Circuit DesignThe BTA-5U2/10U2 Transmitter in-,

corporates RCA MI -27592 solid sateOscillator with two, switchable, temper-ature -controlled crystal positions. Crystalstability is plus or minus 5 Hertz. Thedesired crystal can be selected by meansof a front panel switch or by means of aremote -control switch since relays arebuilt into the exciter. The oscillator em-ploys broadband circuits that require noadjustments. This unit is built on anetched circuit panel easily accessible forservice by removing the cover. The entireoscillator unit can be removed by dis-connecting a cable -plug and retainingscrews. Also a part of the basic exciter isthe 6146 IPA stage which is operated veryconservatively. A pair of 2E26 tubes isused as the first AF stage of the modu-lator circuit.

Select Features

REACH -IN ACCESSIBILITY

Rear view of transmitter with doors removed showing vertical construction permitting com-plete accessibility to all transmitter facilities. The modulation transformer and final PA tankcircuitry are seen in foreground, rear of modulator and blower in center cabinet, wholeheavier components of driver are shown mounted on floor of third cabinet.

BUILT-IN REMOTE CONTROL

Rear view of BTA-10U2 exciter and control cabinet.

CRYSTAL #2

(OPTIONAL)

I

117 V.50/60,v

POWER ECONOMY

Modulator tubes and silicon high voltage rectifierswith cover removed.

STABLE CIRCUIT DESIGN

SOLID STATE

OSCILLATOR - BUFFER

- RADIO FREQ.--- AUDIO FREQ.-- POWER

AUDIOINPUT 0 -

INTERMEDIATEAMPLIFIER

6146

9

DRIVER

4- 400A

POWERAMPLIFIERBTA-5U2=

I -TUBEBTA- OU2=

2 -TUBES5762

ti

L.V. POWERSUPPLYSILICON

BIASSUPPLYSILICON

1ST AUDIOAMPLIFIER

2-2E26

2ND. AUDIOAMPLIFIER

2-4-125A

H.V. POW ER

SUPPLYSILICON

MODULATORFINAL

2-3X3000 F 1

OUTPUTCOUPLING

v

Block diagram of Type BTA-5U2 and BTA-10U2 Transmitters.

The output of the 6146 IPA stage isbroadband and requires no tuning. Itdrives a single 4-400A tube where tuningis accomplished by using a slug -tunedcoil controlled from the front panel. Thistube, in turn, drives one or two high -

efficiency, long life 5762 output triodes.A front panel control of a vacuum vari-able capacitor tunes the plate circuit.

Broadband NeutralizationA new slug -tuned coil was developed

for the power output adjustment and itis driven by a reversible motor. The motoris actuated at the front panel or by re-mote control. The second harmonic trapuses a slug -tuned coil, thus eliminatingthe possibility of contact pitting fromhigh RF currents. Neutralization of thePA is achieved by a broadband trans-former and a variable vacuum capacitor.

The modulator of the transmitter con-sists of a pair of 2E26 tubes located inthe exciter portion, resistance coupled todrive two 4-125A second audio frequencyamplifiers which, in turn, are resistancecoupled to drive a pair of 3X3000F1modulators. These modulator tubes arelow mu triodes, drawing no grid current.They are capable of excellent responseand fidelity. Due to the low plate dissi-pation of the new PA system, the powerinput of the modulator is also reducedaffording appreciable power economies.

Dependable SemiconductorPower Supply

The BTA-5U2/ 10U2 incorporatesRCA silicon rectifiers in the high -voltagecircuits. This rectifier is ideal not only ina combined operation, but even more soin a remote -control application.

The rectifiers are hermetically sealedso they will not be adversely affected byweather conditions. They can operate atambient temperatures ranging from -20degrees to +45 degrees C and at altitudesup to 7500 feet above sea level. There isno significant aging of the forward dropcharacteristics. Across each of the indi-vidual silicon cells a resistor has beenshunted so that they will all share equallythe peak inverse voltage. RCA specifica-tions have been set higher than EIAstandards by adding an additional 30percent peak inverse voltage safety factor.

Cooling SystemThe transmitter is completely air-

cooled. Added refinements such as a de-lay relay have been built-in to keep the

Driver cabinet including exciter and control panel.

blower system in operation for one min-ute after the transmitter has been shutdown. The continued supply of air ex-tends tube life. The exciter cabinet em-ploys convection cooling. A louveredlower back panel and top grill panel pro-vide good ventilation. In the second cabi-net a blower air system distributes air tothe modulator as well as to the PowerAmplifier tubes in cabinet three.

Overload ProtectionTo provide additional reliability, im-

provements were made in the control andprotective circuitry of the transmitter.All primary lines are protected by meansof circuit breakers with instantaneousoverload trip protection. Line and high -

voltage plate circuit breakers have addi-tional built-in thermal protection. The3 -phase blower is protected by a contac-tor with a thermal cutoff in each phase.Relay switching is sequential so that fila-ments will not come on unless the bloweris operating. Low voltage is delayed toallow proper filament heating. The highvoltage is interlocked with the low -voltageand the bias supply so that it will comeon only after the low -voltage and biaspotentials are present. Overload protec-tion is also provided in the low -voltagesupply, the second AF stage, the IPAstage, the modulator, the PA stage andthe high -voltage rectifier. They are in-stantaneous in action and each overloadrelay carries a spare set of contacts wired

to terminals that may be connected to anexternal indicator. A two cycle plateoverload relay also permits the transmit-ter to return to the air automaticallyafter one interruption has occurred.

Starting surges in the plate transformer,high voltage rectifier, and the filter capa-citor are eliminated by the use of a step -start and damping circuit. This at onetime was only available in the higher -power transmitters, but now longer lifeand added reliability are provided in theBTA-5U2/10U2 with the incorporationof these circuits for the suppression ofstarting transients. The damping circuitsand the primary line reactors afford con-tinuous protection against possible opera-tional transients.

Typical floor plan for BTA-5U2 and BTA-10U2 transmitters. External plate transformersare required only fur the BTA-10U2 transmitter since the transformer for the BTA-5U2can be mounted in the PA cabinet.

SEE NOTE -1FEET (MAX) SEE NOTE- 2

:2

pop

'PLATEETA -10U2

Il ONLY

12-.1

2DUMMY LOAD

OPTIONAL

SECONDARY STA-10U2 ONLY WIRE DUCT

oPRIMARY & LINE

Ii'16 D.

26" W.40" H.

TRENCH TO POWER LINEAS CONVENIENT

75

L

UO

DRIVER

JAi. 4r

U U U

MODULATOR &H.V. RECTIFIER

U

P. A .

88" ABOVE FLOOR

OPTIONALPHASING

6

11-

-3426

342

103.50

TRANSMITTER BTA-5U2 / 10U2

DOTTED WALL FOR BTA-SU2 TRANSMITTERDOES NOT ALLOW FOR POWERCONVERSION TO BTA-10U2 TRANSMITTER

IS 1/2 FEETINSIDE WALLS

FOR BTA-SU2 ONLY

hSEE NOTE -3

SPEECH INPUTOPTIONAL

TRENCH TO CONSOLEAS CONVENIENT

REMOTE CONTROLOPTIONAL

342

pw

N

K

-

i,-STEEL COVER

FLOORLEVEL

SHEETMETAL

GROUND STRAP COPPERCONNECT TO BUILDINGFRAMEWORK OR EXTERNALSTATION GROUND.

SECTION AATYPICAL WIRE DUCTCONSTRUCTION INCONCRETE FLOOR

HINGEDCOVER

6X6X12 LG.6 X 6 X24 LG.6 x6 X 60 LG.

OPTIONAL: FLANGED DUCTCONTINENTAL ELEC. EQUIP CO.BOX 1055 CINCINNATI,OHIOCAT. NO. HCW 616, 626 & 656OR APPROVED EQUIVALENTFOR WIRE DUCTS LOCATEDBELOW THE FLOOR

NOTE -I: EXHAUST FAN600-800 RPM APPROX.5000 CFM MOUNTAPPROX. 9.- CFROM FLOOR

NOTE -2: THE MAXIMUMDIMENSIONS SHOWN AREOPTIMUM FOR IOKWTRANSMITTER WITHPHASING MONITORING ANDCONSOLE EQUIPMENT

NOTE -31 DOOR CLEARANCEREQUIRED FOR=CRATED UNITS -44'UNCRATED UNITS -35"

SpecificationsPerformanceAF Input Impedance 150/600 OhmsAF Input Level (100% modulation) +10 ±2 dBmAF Response:

50-7500 Hz ±1 dB30-10,000 Hz ±1.5 dB

AF Distortion (95% modulation):50-10,000 Hz 2.5%

Noise (below 100% modulation) 60 dBFrequency Range 535-1620 kHzFrequency Stability ±5 HzType of Output Single EndedCarrier Shift (0-100% modulation,

400 Hz 3% at constant line voltage5% at normal line voltage regulation

Output Impedance 40-250 Ohms

ElectricalRF Voltage (for Frequency Monitoring) 10 Volts RMS 75 OhmsRF Voltage (for Modulation Monitoring) 10 Volts 75 OhmsPower Output (nominal):

BTA-5U2 5000 WattsBTA-10U2 10,000 Watts

Power Output Capability:BTA-5U2 5500 WattsBTA-10U2 10,600 Watts

Power Source Required 208/240 Volts ±11 VoltsLine Frequency 50/60 HzPhase 3

Power Consumption: BTA-5U2 BTA-10112(0% modulation) 10.0 kW 17.5 kW(100% modulation) 14.5 kW 26.0 kW(Average program modulation) 11.0 kW 21.0 kW

Power Factor 90% 90%

Permissible Combined Line VoltageVariation and Regulation ±5%

Crystal Heater Power 117 Volts 50/60 HzTube Complement:

1 6146 Intermediate Power Amplifier1 4-400A Driver2 2E26 1st Audio Frequency Amplifier2 6155/4-125A 2nd Audio Frequency Amplifier2 3X3000F1 Modulator1 5762 Power Amplifier for BTA-5U22 5762 Power Amplifier for BTA-10U2

MechanicalOverall Height 88" or 223.5 cm

(84" or 213.4 cm less floor channels)Cabinet Height 84" or 213.4 cm

(80" or 203.2 cm less floor channels)Width 1031/2" or 262.9 cmDepth 32" or 81.3 cm (less door handle)Overall Depth 55" or 139.7 cm (with door open)Net Weight:

BTA-10U2 Transmitter 4700 lbs. or 2132 kg. (approx.)Plate Transformer 600 lbs. or 272 kg. (approx.)BTA-5U2 Transmitter

including Plate Transformer 4850 lbs. or 2200 kg. (approx.)Altitude Range 0-7500 ft. (0-2286 m)Ambient Operating Temperature -20°C (-4°F) min.,

+45°C (113°F) max.

AccessoriesComplete Set of Operating Tubes (for BTA-5U2) ES -34233

Complete Set of Operating Tubes (for BTA-10U2) ES -27290

Filament Hours, Elapsed Time indicator* M 1-34684*

Type BTR-11B Remote Control System ES -34280

Type BTA-20D Remote Control System ES -561415

Antenna Tuning Equipment ES -27256

Recommended Spare Tubes for BTA-5U2and BTA-10U2 ES -27291

Type BW-11A AM Frequency Monitor ES -34042

Type BW-66F AM Modulation Monitor M I -30066-B

Alarm Indicator MI -27567

Power Conversion Kit (BTA-51J2 to BTA-10U2) ES -34279-A

Power Cutback Kit 5 kW to 500/1000 W M I -34646-A

Power Cutback Kit 10 kW to 500/1000 W ES -34287

Power Cutback Kit 10 kW to 5 kW ES -34286

Remote RF Pick-up Unitfor powers up to 5 -kW (less meter) M I -27966-B

Remote RF Pick-up Unit for higher powers(less meter) M I -28027-C

Remote Antenna Meter MI -27644-A SeriesRF Ammeter Mounting Hardware MI -27713

°The 5U2/10U2 Transmitter has a blank meter bezel which may be replacedwith an elapsed time indicator, MI -34684. Specify 50 or 60 Hertz.

Ordering InformationType BTA-5U2 Transmitter (including 1 set of tubes

and 1 crystal) ES -27285-B

Type BTA-10U2 Transmitter (including 1 set of tubesand 1 crystal) ES -27286-B

(specify operating frequency and output impedance)

Commercial Electronic Systems DiVision BroadcastFront and Cooper Streets, Camden, New Jersey, U.S.A. 08102 110111 Equipment

catalog B.6500

RCA 1 -KW FM Broadcast Transmitter, Type BTF-1E2

New solid-state exciter

Available for mono or stereo-with or without SCA

Designed for remote control

Direct FM exciter

3T8

ur..) satl

'maximum. 7-Maz,....,'"Ingunmammuzu

New solid-state FM Exciter system, Type BTE-15A, showing"Direct FM" exciter housed with optional stereo generatorand SCA generator units.

RF cavity with shielded cover removed.

DescriptionRCA's Type BTF-1E2 FM Transmit-

ter provides 1,000 Watts output for sta-tions operating in the 88 to 108 MHzband. It is designed to provide the finestpossible performance and reliability, andis specifically built to meet the stringentrequirements of multiplex and stereoservice transmission. It is a simple andcompact unit easy to install.

The BTF-1E2 Transmitter suppliesthe latest in FM broadcast techniques.Only one tube beyond the exciter is re-quired to supply 1000 Watts output. NoIPA stage is required. The transmitteris extremely stable because it incorporatesRCA's time -proven "Direct FM" Exciter.This exciter requires no special tuningor setting up for standard or for multiplexoperations. It has all solid-state com-ponents. Cross -talk and noise are kept toan absolute minimum.

Easy to Install and OperateOther features incorporated in the

BTF-lE2 include silicon rectifiers whichprovide long life with a minimum ofmaintenance. Accessibility is assured bothfront and rear by vertical chassis con-struction, surface mounting of compo-nents, and hinged mounting of theexciter. Mechanical and electrical over-load protection is provided. To assureperformance in accordance with FCCrequirements, the transmitter is suppliedwith harmonic filter. Provisions for re-mote control have been provided in thetransmitter.

High quality FM stereo transmissioncan be obtained by the addition of anRCA BTS-1B Stereo Generator. SCAprogramming may be transmitted simul-taneously with stereo by the use of theoptional BTX-1B subcarrier generator.The BTF-1E2 is type accepted for suchsimultaneous program transmission.

Single CabinetThe Type BTF-1E2 FM Transmitter

is completely housed in one cabinet withtotal floor dimensions of only 26 by 21inches. The cabinet is functionally styledto present a pleasing appearance. Allmeters and operating controls are con-veniently located. Front and rear hingeddoors give easy access to all portions ofthe transmitter.

Located at the front are the overloadrelays, the 1 kW amplifier and RF boxcontaining tuning dials for the amplifier.A control panel and screen supply are lo-cated next, followed by the hingedmounted exciter. Concealed in the bot-tom of the transmitter are the high volt-age rectifier and power transformer. Therear of the transmitter gives access to thebias resistors, metering circuitry andblower, followed by the rear of thecontrol panel and screen supply. A volt-age regulating filament transformer ismounted on the control panel.

Solid -State FM ExciterExcellent monaural, stereo and SCA

performance that more than meets indus-try and FCC standards are achieved bythe new RCA modular, solid-state "DirectFM" exciter.

Simplified CircuitsModulation of the temperature com-

pensated basic on -frequency oscillator isachieved by applying the compositestereo or SCA signals from the BTS-1Band BTX-1B Generators, respectively, toa pair of push-pull varicap diodes whichare coupled to the basic oscillator fre-quency determining resonant circuit. Theoutput of the basic oscillator is isolatedfrom the following buffer amplifier by a10 dB resistive attenuator. Thus, the sta-bility and modulation characteristics ofthe basic direct FM oscillator are notdisturbed by following RF power ampli-fiers.

The output of the buffer amplifier, ap-proximately 500 mW, is used to drivethe 15 -Watt, three -stage RF amplifier aswell as the binary divider chain in theAFC circuit. The basic oscillator, bufferamplifier, and AFC circuit are mountedinside a shielded enclosure. The RFpower amplifier is also completelyshielded.

Automatic frequency control (AFC)for the on -frequency basic oscillator isachieved by taking a sample of the buff-er output frequency and dividing it bytwo, 14 times. A low -frequency referencecrystal operating at 1/1024th of the de-

sired output frequency is divided by two,4 times. Integrated circuits operating inthe saturated mode are used in bothbinary dividing chains. The outputs fromthe reference and basic oscillator binarydividers are phase compared in a time-sharing IC comparator. The output ofthe circuit, which represents the AFCerror voltage, is filtered and applied toanother pair of varicap diodes coupledto the basic oscillator tuned circuit. Thus,the basic oscillator is phase locked to the1024th harmonic of the oven controlledreference crystal.

An off -frequency detector is incorpo-rated in the design of the BTE-15A FMExciter. When the basic oscillator fre-quency is not phase locked to the refer-ence crystal, an AC component appearsat the AFC output. This voltage is recti-fied to operate a relay whose contactscan be used to turn off the FM transmit-ter.

Two multimeters are located on thehinged door of the exciter in front of theregulated power supply section. One ofthese meters is used to indicate powersupply and operating voltages within theexciter and 15 -Watt RF Amplifier. Thesecond meter is a peak -reading voltmeterthat is used to indicate all modulatingsignal levels.

The RF power output of the BTE-15Acan be continuously adjusted from thefront panel control from 7 to 15 Watts.The primary power is turned on with acircuit breaker. RF output is turned on

with a front panel switch or by jumpingcontacts available on the rear of the unit.The exciter will tolerate load mis-matches from short circuit to open cir-cuit for a reasonable time without dam-aging the output transistor. Anothersafety feature prevents turning on the 41kHz SCA subcarrier when the BTS-1BStereo Generator is in the stereo mode.

Power AmplifierThe output of the exciter is fed to the

input of the ceramic 4CX-1000A ampli-fier tube. The amplifier input circuit isa simple parallel resonant circuit, tunedby a variable inductance with resistanceswamping for stability of operation. Thisstage is neutralized by varying inductancein series with the screen. The output cir-cuit is a modified pi network, having avariable inductance across the tube capa-city-which is used to adjust the loading.All capacitors in the final stage are ofthe fixed ceramic type. A blower mountedon the back of the RF compartment pro-vides sufficient filtered air for cooling atstations operating below 7500 feet. Thefilament transformer is of the automaticregulator type and keeps filament voltageconstant within one percent.

The power amplifier is new in manyrespects. The variable inductors use nosliding contacts. There are no variablecapacitors in the power amplifier. Asingle tube, the 4CX1000A, is used inthe BTF-1E2 power amplifier and it isdriven directly by the output of the ex-citer in an exclusive RCA circuit.

Neutralizing ProbeA neutralizing probe is furnished with

the transmitter. It utilizes the multimeterto indicate correct neutralization of thepower amplifier.

The high voltage and screen powersupplies make use of silicon rectifiers ina bridge circuit. This combined withchoke input and adequate filtering re-sults in an excellent well -regulated powersource. A variable transformer is used inthe primary of the screen power supplyto control power output of the transmit-ter. Filament voltage regulation is pro-vided for the 4CX1000A power ampli-fier tube.

Harmonic FilterThe harmonic filter supplied with all

RCA FM transmitters is not a simpleharmonic trap. The filter consists of anM -derived half -T section, several low-pass filter sections, and a constant -K,half -T section. The M -derived sectionprovides rapid cut-off in the second har-monic region, and a termination impe-dance at one end of the filter of 50 Ohms.Attenuation of the harmonics is accom-plished by the low-pass filter sections,while the constant -K, half -T sectionserves to give a termination impedanceof 50 Ohms at the other end of the unit.The use of such a filter assures compli-ance with FCC requirements regardingspurious radiation, as all harmonicsthrough the seventh are effectively at-tenuated.

Simplified Block Diagram of BTF-1E2 Transmitter, showing optional stereo and SCA.

LEFT -P.AUDIO INPUTS

RIGHT -11111

BTS-1BSTEREO

GEN.

STEREO

-10

DIRECT FMOSCILLATOR

AND

BUFFER

EXCITER

R. F.

AMPLIFIER 7- 15 WATTS87-108 MHZ

4CX100APOWER

AMP.

TO

-1111. HARMONIC FILTERAND ANTENNA

SCABTX- I El

SCAGEN.

67 KHz

AFCREFERENCE

CRYSTALOSCILLATOR

EXCITERPOWERSUPPLY

HIGHVOLTAGEPOWERSUPPLY

AUDIO -0INPUT

SCA

At

SCABTX -I B OFF FREQUENCY AC INPUT AC INPUT

AUDIO -0 SCA OFF- FREQ RELAY CONTACTS

SCA TO TRANSMITTERINPUT

GEN. DETECTOR

41 KHz CONTROL CIRCUIT

Protective CircuitsPower circuits are protected by mag-

netically tripped circuit breakers as wellas overload relays. An interlock relayprevents application of plate power un-til the 4CX1000A filament has heatedand the exciter has reached a stable op-erating condition. Overload relays areused in the high voltage and screenpower supplies. There is also an interlockin the air blower circuit. If the blowershould fail or air -flow be reduced belowthe proper level, the transmitter is takenoff the air thus avoiding possible damage.

The overload relays are reset remotelyor by means of an instantaneous keyswitch on the front panel. An overloadindicator lamp signals when an overload

SpecificationsPerformance

has taken place. All relays are easily ac-cessible. Access to high voltage areas isprotected by built-in high voltage short-ing devices.

Control FeaturesThe BTE-15A exciter has a self-con-

tained multimeter. In the amplifier ofthe transmitter, provision is made formetering PA plate current, plate voltage,output power and VSWR; a probe is

furnished for neutralizing the transmitterand is used in connection with the multi -meter. All tuning controls are located onthe front panel for easy accessibility.They include key switches for filamenton -off, plate on -off, and overload reset.The variable power control is also

Type of Emission F3 and F9Frequency Range 88 to 108 MHzPower Output 250-1000 WattsOutput Impedance (15/3" O.D. Line) 50/51.5 OhmsFrequency Deviation, 100% modulation ±75 kHzModulation Capability ±100 kHzCarrier Frequency Stability ±1000 Hz max.Audio Input Impedance 600/150 OhmsAudio Input Level -1(100% mod.) +10±2 dBmAudio Frequency Response -2(50 Hz -15 kHz) ±1 dB max.Pre -emphasis Network Time Constant 75 or 50 p.s

or flat as desiredHarmonic Distortion --3(50 Hz -15 kHz) 0.5% or lessFM Noise Level (referred to 100% FM mod.) -65 dB max.AM Noise Level (referred to 100% AM mod.) -50 dB max.Subcarrier Input Level (100% mod.) -15 to +10 dBm

adjustableSubcarrier Input Impedance 600/150 Ohms bal.Subcarrier Frequency 20-67 kHzMain-to-Subchannel Crosstalk -50 dB referred to

±7.5 kHz deviation of the subcarrier by a 400 Hz tone.Main channel modulation 70% by 50-15,000 Hz tones.

Sub -to -Main -Channel Crosstalk -60 dB referred to±75 kHz deviation of the main carrier by a 400 Hz tone.Subchannel modulated 100% (±7.5 kHz/s) by 50-6000 Hztones. Subcarrier modulated 30% on main carrier.

ElectricalPower Line Requirements:

Line 240/208 Volts, single phase, 60 Hz4Slow Voltage Variation ±5%Power Consumption 2800 Watts (approx.)Power Factor (approx.) 80%

Tube ComplementPower Amplifier:

1-4CX1000A

mounted on the front as are the overloadindicator and plate power -on lights. Theuse of latching relays make it possible tocontrol the transmitter A.% ith one button.

Remote Control ProvisionsThe BTF-1E2 transmitter incorporates

connections for remote control and re-mote meter reading when combined witha remote control system such as the BTR-11B or BTR-20E. Terminals for trans-mitter on -off, plate on -off, overload reset,plate voltage, cathode current, and pow -et output are provided. To control trans-mitter power output remotely, anaccessory motor drive may be connectedto the screen supply control.

MechanicalDimensions (overall) 26" wide, 77" high, 20V deep

(66.04 cm, 195.58 cm, 52.23 cm)Weight 790 lbs. (3.58 kg.)Finish Textured vinyl in midmight blue and

shadow blue, satin aluminum trimAltitude 7500 ft. max. (2290 m)Ambient Temperature Range -20° to +45°C

AccessoriesRecommended Spare RF Transistors for Exciter M1-560718Spare Crystal and Oven

(Specify operating frequency) MI -560717Spare Transmitter Tube MI -34709

1 -kW RF Load and Wattmeter MI-19196L/HType BTR-11B Remote Control System

(10 -function) ES -34280

Type BW-75A FM Frequency andModulation Monitor MI -560735

Type BW-85A FM Stereo Frequency andModulation Monitor M1-560740

Type BW-95A SCA Frequency andModulation Monitor MI -560745

' Level measured at input to pre -emphasis network.Audio Frequency response referred to 75 or 50 micro -second pre -emphasiscurve.Distortion includes all harmonics up to 30 kHz and is measured followinga standard 75 or 50 micro -second de -emphasis network.

' 5U -Hz operation requires Ml -34316-20 regulator.

Ordering InformationType BTF-1E2 1 -kW FM Broadcast Transmitter ....ES -27279-C*

*Please specify assigned frequency, power -line frequencyand altitude of installation and select a BTE-15A ExciterSystem from the following:

Mono ES -560631

Mono and one SCA Channel ES -560632

Mono and two SCA Channels ES -560633

Stereo ES -560634

Stereo and one SCA Channel ES -560635

Stereo and two SCA Channels ES -560636

Corhmercial Electronic Systems Division BroadcastFront and Cooper Streets, Camden, New Jersey, U.S.A. 08102 nen Equipment

catalog B.6505

RCP 5 -KW FM Transmitter, Type BTF-5E1

New solid -stag

Ultra stable-easy to to

Available for mono or stereo-with or without SCA

Field -expandableto 10 or 20 kW

Ready for remote control

5 -KW FM Broadcast Transmitter

CentralizedControls

Ready forremote control

Self -protectedagainst overload

Tilt down chassisfor easy maintenance

Direct -FMExciter

Eye -levelmetering

CompleteAccessibility

Two Stages FollowExciter-IPA and PA

"Filter -Minder"Manometer

FullyAir Cooled

Full -Fidelity FM Transmitter, Type BTF-5E1RCA's Type BTF-5E1 FM Broadcast

Transmitter provides 5,000 Watts output forstations operating in the 88 to 108 MHzband. It is designed to provide the finest pos-sible performance and reliability, and isspecifically built to meet or exceed thestringent requirements of multiplex servicetransmission. The equipment is FCC typeaccepted and meets all requirements for har-monic and spurious emission.

The BTF-5E1 employs a new exciter thatuses the time -tested and field -proven direct -FM system. The circuit uses capacitivediodes as modulators of an oscillator to pro-duce direct FM. Automatic frequency -control maintains oscillator frequency toclose tolerances under virtually all operatingconditions.

Because of its wide frequency response andextreme stability, the exciter (and the trans-

mitter) is ideally suited for multiplex andstereo programming.

The Type BTA-15A Exciter in the BTF-5E1 uses all solid-state components for longlife and great dependability. For ease oftuning, the exciter has a built-in multimeterand highly -accessible test points permittingconvenient metering and checking whileoperating.

Frequency response of the transmitter'smain channel is 30 to 15,000 Hz (±1 dBmaximum) and the distortion over the samebandwidth is less than one-half of one per-cent.

The BTF-5E1 is designed specifically tobe field -expandable to a 10- or 20 -kW trans-mitter. It is noteworthy that this expansionis substantially electrical and there is virtu-ally no increase in floor -space requirements.

DescriptionMono or Stereo

The transmitter features a new exciterdesigned for stereo and multiplex. Theexciter, including its self-contained powersupply, is mounted on a single verticalchassis.

Two Stages Follow ExciterFrom the 15 -Watt output of the exciter,

only two tubes generate the full 5 -kWsignal. A harmonic filter is included toreduce spurious radiation. ;Vacuum capa-citors are used to tune the IPA plate andthe PA grid.

Ready for Remote ControlThe transmitter is designed and built

for remotely -controlled operation. Inter-nal wiring and terminals are provided forremote control of these transmitter func-tions: transmitter on/off; raise/lower out-put power and overload reset. Remotemetering facilities for the PA include:cathode current; plate voltage and poweroutput.

New StylingFunctional styling combined with fewer

tubes permits the BTF-5E1 to be housed

in a single, double -door cabinet in a newmidnight blue and shadow blue vinylfinish. For contrast, the meter panel is inbright aluminum and the cabinet istrimmed in satin -finished aluminum. Theswing -out doors in the front and rear af-ford the excellent accessibility for whichRCA transmitters are famous.

All operating controls and meters aremounted on a panel above the front doors.

BTE-15A FM ExciterExcellent monaural, stereo and SCA



pensated basic on -frequency oscillator isachieved by applying the compositestereo or SCA signals from the BTS-1Band BTX-1B Generators, respectively, toa pair of push-pull varicap diodes whichare coupled to the basic oscillator fre-quency determining resonant circuit. Theoutput of the basic oscillator is isolatedfrom the following buffer amplifier by a

10 dB resistive attenuator. Thus, the sta-bility and modulation characteristics ofthe basic direct FM oscillator are not dis-turbed by following RF power amplifiers.

The output of the buffer amplifier, ap-proximately 500 mW, is used to drive the15 -Watt, three -stage RF amplifier as wellas the binary divider chain in the AFCcircuit. The basic oscillator, buffer ampli-fier, and AFC circuit are mounted in-side a shielded enclosure. The RF poweramplifier is also completely shielded.

"On Carrier" Frequency OperationAutomatic frequency control (AFC)

for the on -frequency basic oscillator isachieved by taking a sample of the bufferoutput frequency and dividing it by two,14 times. A low -frequency reference cry-stal operating at 1/1024th of the desiredoutput frequency is also frequency dividedby 16 in a binary chain. Integrated cir-cuits operating in the saturated mode areused in both binary dividing chains. Theoutputs from the reference and basic os-cillator binary dividers are phase com-pared in a time-sharing IC comparator.The output of the circuit, which repre-sents the AFC error voltage, is filtered

Select Features

BTF-5E1 Control Panel. Tally lights and push-button controls simplify operation.

I 0 0The large -diameter multimeter knobs

speed log -keeping and minimize error.

and applied to another pair of varicapdiodes coupled to the basic oscillatortuned circuit. Thus, the basic oscillatoris phase locked to the 1024th harmonicof the oven controlled reference crystal.

An off -frequency detector is incorpo-rated in the design of the BTE-15A FMExciter. When the basic oscillator fre-quency is not phase locked to the refer-ence crystal, an AC component appearsat the AFC output. This voltage is recti-fied to operate a relay whose contacts canbe used to turn off the FM transmitter.

Two multimeters are located on thehinged door in front of the regulatedpower supply section. One of these metersis used to indicate power supply and op-erating voltages within the exciter and15 -Watt RF Amplifier. The second meter


is a peak -reading voltmeter that is usedto indicate all modulating signal levels.

The RF power output of the BTE-15Acan be continuously adjusted from thefront panel control from 7 to 15 Watts.The primary power is turned on with acircuit breaker. RF output is turned onwith a front panel switch or by jumpingcontacts available on the rear of the unit.The exciter will tolerate load mismatchesfrom short circuit to open circuit for areasonable time without damaging theoutput transistor. Another safety featureprevents turning on the 41 kHz SCA sub -carrier when the BTS-1B Stereo Gener-ator is in the stereo mode.

Class "C" Power AmplifiersTwo simplified, single -ended ampli-

fiers operating class "C" follow the ex-citer. The 250 -Watt driver stage uses aType 7203/4CX250B tube, and the finalpower amplifier uses a Type 4CX5000A(ceramic tetrode). Vacuum variable ca-pacitors tune the pi network betweendriver and PA. The power amplifier, too,uses pi -network circuitry and tuning is

accomplished by variable inductors oper-ating at ground potential.

5 -kW Class "C" Final AmplifierThe output tube, a ceramic tetrode,

4CX5000A, offers very high power -gainwith little drive. Using this tube, onlytwo stages of amplification are requiredbetween the exciter and the antenna forthe 5,000 -Watt output. Fewer compo-nents result in improved reliability.

Motor -Driven Power -Output ControlPower output is controlled by means of

a motor -driven variable transformerwhich controls the low -voltage power sup-ply. This supply controls the driver -plateand the screen voltages of both stagessimultaneously. A separate grid bias sup-ply increases transmitter stability and re-liability. The use of semi -conductor(silicon) rectifiers reduces operating andmaintenance costs.

Harmonic Filter StandardEquipment

To keep spurious emission to a mini-mum, a harmonic filter is standard equip-ment with the BTF-5E1. The filterconsists of an "M" -derived "half -T" sec-tion, several low-pass filter sections, and aconstant -"K", "half -T" section. Attenua-tion of the harmonics through the seventhis accomplished by the passband of tbelow-pass filter sections, while the constant -

"K", "half -T" section serves as a 50 -Ohmtermination impedance.

Self -Protected Against OverloadPower circuits are protected by mag-

netically -tripped circuit breakers in addi-tion to overload relays. An interlocksystem prevents turn -on of plate poweruntil all filaments have heated and theexciter has reached a proper operatingcondition. In addition, a latching relayautomatically re -applies power to thetransmitter once before locking -out inthe event of brief overloads or power in-terruptions. The overload relays are resetby illuminated push button switches onthe front panel. Separate tally -light indi-cators are provided for overloads in thedriver, power amplifier and low -voltagerectifier circuits.

Fully Air -CooledCooling air for the BTF-5E1 is sup-

plied by a blower mounted below the

amplifier stages. Heavy sound insulationreduces blower noise to a minimum. Theblower supplies forced air to both theIPA and PA stages.

Simplified ControlThe transmitter has all operating con-

trols and meters located on a panel justabove the front doors. The push-buttoncontrols include: transmitter on/off,plate on/off, overload reset and powerraise/lower. A cabinet disconnect switch,low -voltage circuit breaker, and filamentcontrol circuit breakers are located be-hind the left-hand door. The main- andlow -power circuit breakers are located inthe unitized rectifier cabinet. When serv-icing the BTF-5E1, operation of the dis-connect switch removes all voltages fromthe transmitter cabinet. Personnel are alsoprotected by fully interlocked rear doorsin addition to interlocked doors on thePA cubicle.

Simplified Block Diagram of the BTF-5E1 Transmitter, showing optional stereo and SCA.

LEFT 11

BTS -18AUDIO INPUTS STEREO

RIGHTGEN.

STEREO0, DIRECT FM

OSCILLATORAND

BUFFER

SCABTX-1B

SCAAUDIO -00SCAGEN.

INPUT67 KHz

BTX-IBSCA

AUDIO -00 SCA 4-SCAGEN.

INPUT41 KHz

A FC

EXCITERR. F.

AMPLIFIER

OFF-FREQ.DETECTOR

REFERENCECRYSTAL

OSCILLATOR

OFF FREQUENCYRELAY CONTACTS

TO TRANSMITTER

CONTROL CIRCUIT

7-15 WATTS87-108 MHz

DRIVER

7203/4CX2506

PA

4CX500 OA

EXCITER VARIABLE HIGH VOLTAGE PAPOWER LOW VOLTAGE SUPPLY BIAS SUPPLYSUPPLY SUPPLY

Full MeteringSix easy -to -read front -panel meters are

provided for each amplifier. One for PA -plate voltage, another for PA -plate cur-rent, and a third for AC line and filamentvoltage. The remaining three are a re-flectometer indicating output, a multi -meter, and VSWR meter. Separatemeters are used to measure the forwardpower and VSWR. The multimeter readsgrid current, screen current and screenvoltage of both power tubes. In additionthe exciter has its own self-containedmultimeter. This one provides completeinformation on operating conditions inthe exciter.

Ready for Remote ControlRemote control provisions are included

in the transmitter, and terminals are pro-vided for use with remote control unitssuch as the Type BTR-11B or BTR-20Dand Automatic Logging Equipment. Ad-ditional terminals are provided for re-mote control of transmitter on/off, plateon/off, raise/lower power, and overloadreset. Remote metering connections inthe final amplifier for plate current, platevoltage, and power output are also pro-vided.

High -Voltage Power SupplyThe high -voltage power supply is

housed in a unitized cabinet measuring

ONLY TWO TUBES BETWEEN EXCITER AND OUTPUT-Viewshowing interior of PA and IPA cabinet with the 4CX5000Aceramic tetrode and one 7203/4CX250B IPA tube below shelf.

27 inches wide, 23 inches deep and 43inches high. It can be installed at anyconvenient site in the station. The cabi-net houses the high -voltage -plate trans-former, a bank of plug-in semiconductorrectifiers, a line -circuit breaker, a high -voltage circuit breaker, and the plate con-tactor. Personnel are fully protected fromshock through interlock and groundingswitches.

The rectifier section comprises silicon -junction diodes (with equalizing resistorsand capacitors) in a three-phase, full -wave -bridge circuit. Circuit breakers areused instead of fuses in the transmitteradding to the dependability, particularlywhen operating remote control.

COMPLETE ACCESSIBILITY-Rear view of the BTF-5E1 re-vealing the clean, vertical construction of PA cavity to leftand control panel to right.

UNITIZED HIGH VOLTAGE POWER SUPPLY-With location not tied to the transmitter, theunitized power supply affords many installa-tion and operating economies.

MODULAR SILICON RECTIFIERS-Qualitycomponents such as this plug-in silicon high -voltage rectifier are important elements in theBTF-5E1's superior performance.

SpecificationsPerformanceType of Emission F3 and F9

Frequency Range 88 to 108 MHz

Power Output 5 kW

Output Impedance (31/2" O.D. Line) 50 Ohms

Frequency Deviation 100% modulation ±75 kHz

Modulation Capability ±100 kHz

Carrier Frequency Stability ±1000 Hz max.

Audio Input Impedance 600/150 Ohms

Audio Input Level-*(100% mod.) +10 ±2 dBmAudio Frequency Response-**(50-15,000 Hz) ±1 dB max.

Pre -emphasis Network Time Constant 75 or 50 µs, as desired

Harmonic Distortion-***(50-15,000 Hz) 0.5% or lessFM Noise Level (referred to 100% FM mod.) -65 dB max.AM Noise Level (referred to 100% AM mod.) -50 dB max.Subcarrier Input Level (100% mod.) -15 to +10 dBm

adjustable

Subcarrier Input Impedance 600/150 Ohms bal.

Subcarrier Frequency 20-67 kHz

Main-to-Subchannel Crosstalk.... -50 dB referred to ±7.5 kHzdeviation of the subcarrier by a 400 Hz tone. Main chan-nel modulation 70% by 50-15,000 Hz tones.

Sub -to -Main -Channel Crosstalk.... -60 dB referred to ±75 kHzdeviation of the main carrier by a 400 Hz tone. Subchan-nel modulation 100% (±7.5 kHz) by 50-6000 Hz tones.Subcarrier modulated 30% on main carrier.


Line 240/208 Volts, 3 phase, 50/60 HzCombined Line Voltage Variation and Regulation ±5%Power Consumption 10,000 Watts (approx.)Power Factor (approx.) 90%

Crystal Heater:Line 117 Volts, single phase, 50/60 HzPower Consumption 71/2 Watts

Tube ComplementDriver:

1-7203/4CX250BPower Amplifier:

1-4CX5000A

MechanicalDimensions (overall): Transmitter

High -Voltage,Power Supply

Width ........... .............. 481/2" (123 cm) 27" (68.6 cm)Height 77" (195.6 cm) 43" (109.2 cm)Depth - 321/2" (82.5 cm) 23" (58.5 cm)Weight (approx.) 1250 lbs. (567 kg.) 590 lbs. (267.6 kg.)

Finish Textured Vinyl in midnight blue andshadow blue, satin -aluminum trim.

Altitude 7500 ft.t (2290 M)

Ambient Temperature Range -20° to +45°C

* Level measured at input terminal J1.*" Audio Frequency response referred to 50- or 75 -microsecond pre -emphasis

curve.*** Distortion includes all harmonics up to 30 kHz and is measured

following a standard 50- or 75 -microsecond de -emphasis network.t Blowers can be provided for operation at higher altitudes.

Specifications subject to change without notice.

12"MIN.

12" M NIMUM36" RECOMMENDED

27"

6"

POWERSUPPLY

LOCATIONOPTIONAL

TO INCOMINGPOWER SOURCE

00

EXHAUST FAN 5000 CFM

24" MINIMUM36" RECOMMENDED

14-4

TRANSMITTER

32k" HARMONIC FILTER

48--2

DIRECTION OPTIONAL

17.50

-IL- TO ANTENNA

FREQ. MHz MI A

88-98 27967-I 140.29

98-108 27967-2 129.38

Space -saving floor plan of the BTF-5E1. The separate, unitized power supply may be installed inthe basement, attic, closet, or other convenient place. (Wire duct and fan shown are not furnished.)

Accessories

Recommended Spare RF Transistors for Exciter MI -560718

Spare Crystal and Oven(Specify operating frequency) MI -560717

5 -kW RF Load and Wattmeter M1-561422

Type BTR-11B Remote Control System(10 -function) ES -34280

Ordering InformationType BTF-5E1 5 -kW FM Transmitter ES -560600*

*Please specify assigned frequency, power -line frequency,and altitude of installation and select BTE-15A ExciterSystem from the following:

Type BTR-20D Remote Control System(20 -function) ES -34274-C


Type BW-85A Stereo Frequency andModulation Monitor M1-560740


Mono ES -560631



Stereo ES -560634


Stereo and two SCA Channels 'ES -560536

Commercial Electronic Systems DivisionBroadcast

Front and Cooper Streets, Camden, New Jersey, U.S.A. 08102 non Equipment

catalog B.6510

10 -KW FM Transmitter,

1-1=1-1=1-1a


CentralizedControls


Self -protectedagainst overload


Direct -FMExciter

(44) 0 0 Mu/

'2 I 2000 fit

-eI

ti

0

d

Optional StereoSub -Carrier Generator

FullyAir Cooled

Eye -levelmetering



"Filter -Minder"Manometer

Full -Fidelity FM Transmitter, Type BTF-10E1RCA's Type BTF-10E1 FM Broadcast

Transmitter provides 10,000 Watts outputfor stations operating in the 88 -to -108 MHzband. It is designed to provide the finestpossible performance and reliability, and isspecifically built to meet or exceed the strin-gent requirements of multiplex service trans-mission. The equipment is FCC type ac-cepted and meets all requirements for har-monic and spurious emission.

The BTF-10E1 employs a new type BTE-15A Exciter that uses the time -tested andfield -proven RCA Direct FM System. Thecircuits employ all solid-state components.Their inherent long -life and cool operationassure extended reliability and lend them-selves particularly to unattended, remoteoperation.

Frequency response of the transmitter'smain channel is 30 to 15,000 Hz (±1 dBmaximum) and the distortion over the samebandwidth is less than one-half of one per-cent.

A new feature of the transmitter is thebuilt-in manometer. This device indicatesair -filter efficiency and warns of reducedcooling -air supply over the power tubes.Properly used, the manometer can add hun-dreds of hours to power -tube life.

The BTF-10E1 is designed specifically tobe field -expandable to a 20 -kW transmitter.It is noteworthy that this expansion is sub-stantially electrical and there is no increasein floor -space requirement.


The transmitter features a new exciterdesigned for stereo and multiplex. Theexciter, including its self-contained powersupply, is mounted on a single verticalchassis.

Two Stages Follow ExciterFrom the 15 -Watt output of the exciter,

only two tubes are required for full 10 -kWoutput. A harmonic filter is included toreduce spurious radiation. Vacuum capac-itors are used to tune the IPA plate andthe PA grid. In the power amplifiers, alladjustments are at ground potential.

Ready for Remote ControlThe transmitter is designed and built

for remotely -controlled operation. Internalwiring and terminals are provided for re-mote control of these transmitter func-tions: transmitter on/off; output powerraise/lower and overload reset. Remotemetering facilities for the PA include:cathode current; plate voltage and poweroutput.

New StylingFunctional styling combined with fewer

tubes permits the BTF-10E1 to be housedin a single, double -door cabinet in a newmidnight blue and shadow blue texturedvinyl finish. For contrast, the meter panelis in bright aluminum and the cabinetis trimmed in satin -finished aluminum.The swing -out doors in the front and rearafford the excellent accessibility for whichRCA transmitters are famous.

Operating controls and meters aremounted on a panel above the front doors.

Field Expandable to 20 -kWSince the BTF-10E1 is, basically, a

20 -kW transmitter operating at 10 -kW, itis readily modified, after installation, toa 20 -kW output. It is noteworthy thatthis expansion in power capability re-quires no additional floor space.

Expansion of the power output is par-ticularly valuable if the station using aBTF-10E1 decides to combine horizon-tally- and vertically -polarized signals. Thisfeature avoids any change in floor planas a result of the power increase.


performance that more than meets indus-try and FCC standards are achieved bythe new RCA modular, solid-state "Di-rect FM" exciter.


pensated basic on -frequency oscillator isachieved by applying the composite stereoor SCA signals from the BTS-1B andBTX-1B Generators, respectively, to apair of push-pull varicap diodes whichare coupled to the basic oscillator fre-quency determining resonant circuit. Theoutput of the basic oscillator is isolatedfrom the following buffer amplifier by a10 dB resistive attenuator. Thus, the sta-bility and modulation characteristics ofthe basic direct FM oscillator are not dis-turbed by following RF power amplifiers.

The output of the buffer amplifier, ap-proximately 500 mW, is used to drive the15 -Watt, three -stage RF amplifier as wellas the binary divider chain in the AFCcircuit. The basic oscillator, buffer ampli-fier, and AFC circuit are mounted in-side a shielded enclosure. The RF poweramplifier is also completely shielded.

Select Features


0The large -diameter multimeter knobs

speed log -keeping and minimize error.


for the on -frequency basic oscillator isachieved by taking a sample of the bufferoutput frequency and dividing it by two,14 times. A low -frequency reference crys-tal operating at 1/1024th of the desiredoutput frequency is divided by two, 4times. Integrated circuits operating in thesaturated mode arc used in both binarydividing chains. The outputs from the ref-erence and basic oscillator binary dividersare phase compared in a time-sharing ICcomparator. The output of the circuit,which represents the AFC error voltage,is filtered and applied to another pair ofvaricap diodes coupled to the basic oscil-

a


lator tuned circuit. Thus, the basic oscil-lator is phase locked to the 1024th har-monic of the oven controlled referencecrystal.


Two multimeters are located on thehinged door in front of the regulatedpower supply section. One of these metersis used to indicate power supply and op-erating voltages within the exciter and

15 -Watt RF Amplifier. The second meteris a peak -reading voltmeter that is usedto indicate all modulating signal levels.

The RF power output of the BTE-15Acan be continuously adjusted from thefront panel control from 7 to 15 Watts.The primary power is turned on with acircuit breaker. RF output is turned onwith a front panel switch or by jumpingcontacts available on the rear of the unit.The exciter will tolerate load mismatchesfrom short circuit to open circuit for areasonable time without damaging theoutput transistor. Another safety featureprevents turning on the 41 kHz SCA sub -carrier when the BTS-1B Stereo Gen-erator is in the stereo mode.

Class "C" Power AmplifiersTwo simplified, single -ended ampli-

fiers, operating in class "C", follow theexciter. The 250 -Watt IPA stage uses aType 7203/4CX250B tube, and the finalpower amplifier uses a Type 4CX10000A(ceramic) tetrode. Vacuum variable ca-pacitors tune the pi network betweendriver and PA. The power amplifier, too,uses pi -network circuitry and tuning isaccomplished by variable inductors oper-ating at ground potential.

10 -kW Class "C" Final AmplifierThe output tube, a ceramic tetrode,

4CX10000D, offers very high power -gainwith little drive. Using this tube, only twostages of amplification are required be-tween the exciter output and the antennafor the 10,000 -Watt output. Fewer com-ponents result in improved reliability.

Motor -Driven Power -Output ControlPower output is controlled by means

of a motor -driven variable transformer

which controls the low -voltage power sup-ply. This supply controls the driver -plateand the screen voltages of both stagessimultaneously. A separate grid bias sup-ply increases transmitter stability andreliability. The use of semiconductor(silicon) rectifiers reduces operating andmaintenance costs.


To keep spurious emission to a min-imum, a harmonic filter is standard equip-ment with the BTF-10E1. The filter con-sists of an "M" -derived "half -T" sections,several low-pass filter sections, and a con-stant -"K", "half -T" section. Attenuationof all harmonics through the seventh isaccomplished by the passband of thelow-pass filter sections, while the con-stant -"K", "half -T" section serves as a50 -Ohm termination impedance.


netically -tripped circuit breakers in addi-tion to overload relays. An interlock sys-tem prevents turn -on of plate power untilall filaments have heated and the ex-citer has reached a proper operating con-dition. In addition, a latching relay auto-matically re -applies power to the trans-mitter once before locking -out in theevent of transient overloads or powerinterruptions. The overload relays arereset by illuminated push button switcheson the front panel. Separate tally -lightindicators are provided for overloads inthe driver, power amplifier and low volt-age rectifier circuits.


plied by a squirrel -cage blower mountedbelow the amplifier stages. Heavy soundinsulation reduces blower noise to a min-imum. The blower supplies forced air toboth the IPA and PA stages.

Since the "drag" of a clogged air filtercan reduce power -tube life, the transmit -

Simplified block diagram of BTF-10E1, showing optional stereo and SCA.

LEFT

AUDIO INPUTS

RIGHT -0.

SCAAUDIO -90INPUT

STEREO

BTS -18STEREO

GEN.

BTX - I B

SCAGEN

67 KHz

SCAAUDIO -110INPUT

BTX-IBSCAGEN.

41 KHZ

SCA

SCA

DIRECT FMOSCILLATOR

AND

BUFFER

A FC

EXCITER

R. F.

AMPLIFIER

OFF -FRED.DETECTOR

REFERENCECRYSTAL

OSCILLATOR


TO TRANSMITTER

CONTROL CIRCUIT

7- 15 WATTS87-10B MHZ

DRIVER7203/4CX250B

PA

4CX10000A

EXCITER VARIABLEHIGH VOLTAGE PA

POWER LOW VOLTAGE SUPPLY BIAS SUPPLYSUPPLY SUPPLY

ter monitors this drag with a high -resolu-tion manometer. This device senses therelative air pressure at the fan "side" ofthe fiber -glass filter in inches of water.Properly monitored, the manometer indi-cates when filter clog has reduced thevolume of cooling air supplied to thepower tubes. Maintenance of filter effi-ciency is very important..in realization ofthe potential life of the power tubes.


trols and meters located on a panel justabove the front doors. The push-buttoncontrols include: transmitter on/off, plate

on/off, overload reset and power raise/lower. A cabinet disconnect switch, low -voltage circuit breaker, and filament con-trol circuit breakers are located behindthe left-hand door. The main- and low -power circuit breakers are located in theunitized rectifier cabinet. When servicingthe BTF-10E1, operation of the discon-nect switch removes all voltages from thetransmitter cabinet. Personnel are alsoprotected by fully interlocked rear doorsin addition to interlocked doors on thePA cubicle.


ONLY TWO TUBES BETWEEN EXCITER AND OUTPUT-Viewshowing interior of PA and IPA cabinet with the 4CX10000Aceramic tetrode and one 7203/4CX250B IPA tube below shelf.These supply the necessary power for the full fidelity BTF-10E1.

provided for each amplifier. One for PA -plate voltage, another for PA -plate cur-rent, and a third for AC line and filamentvoltage. The remaining three are a re-flectometer indicating output, a multi -meter and VSWR meter. Separate metersare used to measure the forward powerand VSWR. The multimeter reads gridcurrent, screen current and screen volt-age of both power tubes. In addition tothis metering, the exciter has its ownself-contained multimeter. This one pro-vides complete information on operatingconditions in the exciter.


a 0

UNITIZED HIGH VOLTAGE POWER SUPPLY-.With location not tied to the transmitter, theunitized power supply affords many installationand operating economies.

MODULAR SILICON RECTIFIERS-Quality componentssuch as this plug-in silicon high voltage rectifier are im-portant elements in the BTF-10E1's superior performance.


Frequency Range 88 to 108 MHz

Power Output 10 kW


Frequency Deviation 100% modulation ±75 kHz

Modulation Capability ±100 kHz

Carrier Frequency Stability ±1000 Hz max.

Audio Input Impedance 600/150 Ohms

Audio Input Level-*(100% mod.) +10 ±2 dBmAudio Frequency Response-**(50-15,000 Hz) ±1 dB max.

Pre -emphasis Network Time Constant 75 or 50 /Is, as desired

Harmonic Distortion-***(50-15,000 Hz) 0.5% or less

FM Noise Level (referred to 100% FM mod.) -65 dB max.AM Noise Level (referred to 100% AM mod.) -50 dB max.

Subcarrier Input Level (100% mod.) -15 to +10 dBmadjustable

Subcarrier Input Impedance 600/150 Ohms bal.



Sub -to -Main Channel Crosstalk.... -60 dB referred to ±75 kHzdeviation of the main carrier by a 400 Hz tone. Subchan-nel modulation 100% (±7.5 kHz) by 50-6000 Hz tones.Subcarrier modulated 30% on main carrier.


Line 240/208 Volt, 3 phase, 50/60 HzCombined Line Voltage Variation and Regulation ±5%Power Consumption 19,000 Watts (approx.)Power Factor (approx.) 90%


1-7203/4CX250B

Power Amplifier:1-4CX10000A

MechanicalDimensions (overall): Transmitter

High VoltagePower Supply

iWidth 481/2" (123 cm) 27" (68.6 cm)

Height 77" (195.6 cm) 43" (109.2 cm)

1 Depth 321/2" (82.5 cm) 23" (58.5 cm)Weight (approx.) ..._.. 1300 lbs. (589.7 kg.) 840 lbs. (381 kg.)




Level measured at input terminal .11.

** Audio Frequency response referred to 50- or 75 -microsecond pre -emphasiscurve.

*** Distortion includes all harmonics up to 30 kHz and is measuredfollowing a standard 50- or 75 -microsecond de -emphasis network.

t Blowers can be provided for operation at higher altitudes.


12"MIN.

6" t-

Ic 1

12" M NIMUM36" RECOMMENDED

27"

POWERSUPPLY

LOCATION

o OPTIONAL

cc


t

EXHAUST FAN 5000 CFM

24" MINIMUM36" RECOMMENDED

000

I I'144

TRANSMITTER

32in2 HARMONIC FILTER

48-2

DIRECTION OPTIONAL

17.50

--FLTO ANTENNA

FREQ. MHz MI A

88- 98 27967-I 140.29

98- 108 27967-2 129.38

Space -saving floor plan of the BTF-10E1. The separate, unitized power supply may be installed ina basement, attic, closet or other convenient place. (Wire duct: and fan shown are not furnished.)

AccessoriesRecommended Spare RF Transistors for Exciter MI -560718Spare Crystal and Oven

(Specify operating frequency) MI -560717Complete Set of Spare Tubes ES -56060810 -kW RE Load and Wattmeter MI -19267Type BTR-11B Remote Control System


Ordering InformationType BTF-10E1 10 -kW FM Transmitter ES -560601

Please specify assigned frequency, power -line frequencyand altitude of installation and select BTE-15A ExciterSystem from the following:



Type BW-85A Stereo Frequency andModulation Monitor MI -560740

Type BW-95A SCA Frequency andModulation Monitor Ml -560745

Mono ES -560631Mono and one SCA Channel ES -560632Mono and two SCA Channels ES -560633Stereo ES -560634Stereo and one SCA Channel ES -560635Stereo and two SCA Channels ES -560636

Commercial Electronic Systems Division BroadcastFront and Cooper Streets, Camden, New Jersey, U.S.A. 08102 n Equipment

catalog B.6520

20 -KW FM Transmitter, ype BTF-20E1AIIIIMM1111=1111111111111


CentralizedControls


Self -protectedagainst merload


Direct -FMEkciter

t 2I 000 It IL

--o

11111 MSILIENITIM.11..111 Min Lin

ig

a

dl

Eye -levelmetering



'Filter -Minder"Manometer

Rack Spacefor Optional Stereo

Sub -Carrier Generator

FullyAir Cooled

Full -Fidelity FM Transmitter, Type BTF-20E1

The RCA Type BTF-20E1 20 -kW TMBroadcast Transmitter is designed for high -power operation in the standard FM band,88-108 MHz, and is specifically engineeredto meet and exceed the stringent require-ments of multiplex service transmission andstereo programming as specified by the FCC.

The BTF-20E1 employs a new Type BTE-15A Exciter that uses the time -tested andfield -proven direct FM system. The circuitsemploy all solid-state components. Their in-herent long -life and cool operation assureextended reliability and lend themselves par-ticularly to unattended, remote operation.

The transmitter features a Type 4CX-15000A Power Amplifier driven by two7203/4CX250B tubes in the IPA stage.

Silicon -rectifier power supplies also providelong life and dependability. All RF circuitsare single tuned for utmost tuning simplici-ty. Except for the high voltage power supply,the transmitter is housed in a single, modern -styled, two -door cabinet.

Frequency response of the transmitter'smain channel is 30 to 15,000 Hz (±1 dBmaximum) and distortion over the samerange is 0.5 percent or less.

A useful feature of the transmitter is thebuilt-in manometer. This device indicates

'air filter efficiency and warns of reducedcooling -air supply over the power tubes.Properly used, this device can add hundredsof hours to tube life.


The transmitter features a new exciterdesigned for stereo and multiplex. The ex-citer, including its self-contained powersupply, is mounted on a single verticalchassis.

Two Stages Follow ExciterFrom the output of the exciter, only

three tubes, two in the IPA and a ceramic-tetrode 4CX-15000A PA generate the full20 -kW signal. A harmonic filter is fur-nished to reduce spurious radiation.

Vacuum capacitors are used to tune theIPA plate and PA grid. In the power am-plifier, all adjustments are at ground po-tential.

Ready for Remote ControlThe transmitter has been designed and

built for remote controlled operation.Terminals are provided for remote controlof transmitter on/off, raise/lower powerand overload reset, while remote meteringconnections for the PA include cathodecurrent, plate voltage and power output.

New StylingFunctional styling together with fewer

tubes and components has permitted thenew BTF-20E1 transmitter to be housedin a single, double -door cabinet, in a newmidnight blue and shadow blue finish, setoff with aluminum meter panel and trim.Maximum accessibility is afforded byswing -out doors on the front and rearof the cabinet. All operating controls andmeters used for rapid check of transmitterfunctions are located on a panel abovethe front doors. A separate unitized high -voltage power supply may be located any-where in the FM station.




pensated basic on -frequency oscillator is

achieved by applying the composite stereoor SCA signals from the BTS-1B andBTX-1B Generators, respectively, to a pairof push-pull varicap diodes which arecoupled to the basic oscillator frequencydetermining resonant circuit. The outputof the basic oscillator is isolated from thefollowing buffer amplifier by a 10 dB re-sistive attenuator. Thus, the stability andmodulation characteristics of the basicdirect FM oscillator are not disturbed byfollowing RF power amplifiers.

The output of the buffer amplifier, ap-proximately 500 mW, is used to drive the15 -Watt, three -stage RF amplifier as wellas the binary divider chain in the AFCcircuit. The basic oscillator, buffer ampli-fier, and AFC circuit are mounted insidea shielded enclosure. The RF power am-plifier is also completely shielded.

Automatic frequency control (AFC)for the on -frequency basic oscillator isachieved by taking a sample of the bufferoutput frequency and dividing it by two,14 times. A low -frequency reference crys-tal operating at 1/1024th of the desired

Select Features


40 QThe large -diameter multimeter knobsspeed log -keeping and minimize error.

output frequency is divided by two, 4times. Integrated circuits operating in thesaturated mode are used in both binarydividing chains. The outputs from thereference and basic oscillator binary di-viders are phase compared in ,a time-sharing IC comparator. The output of thecircuit, which represents the AFC errorvoltage, is filtered and applied to anotherpair of varicap diodes coupled to thebasic oscillator tuned circuit. Thus, thebasic oscillator is phase locked to the1024th harmonic of the oven controlledreference crystal.

2


An off -frequency detector is incorpo-rated in the design of the BTE-15A FMExciter. When the basic oscillator fre-quency is not phase locked to the referencecrystal, an AC component appears at theAFC output. This voltage is rectified tooperate a relay whose contacts can beused to turn off the FM transmitter.

Two multimeters are located on thehinged door in front of the regulatedpower supply section. One of these metersis used to indicate power supply and op-erating voltages within the exciter and 15 -Watt RF Amplifier. The second meter is

a peak -reading voltmeter that is used toindicate all modulating signal levels.

The RF power output of the BTE-15Acan be continuously adjusted from thefront panel control from 7 to 15 Watts.The primary power is turned on with acircuit breaker. RF output is turned onwith a front panel switch or by jumpingcontacts available on the rear of the unit.The exciter will tolerate load mismatchesfrom short circuit to open circuit for areasonable time without damaging theoutput transistor. Another safety featureprevents turning on the 41 kHz SCA sub-

carrier when the BTS-(B Stereo Generatoris in the stereo mode.

Single -Ended Driver AmplifierTwo simplified, single -ended amplifiers

(operating Class "C": follow the exciter.The IPA stage consists of two ceramic7203/4CX250B tetrocles operating in par-allel, and the final power amplifier is Type4CX15000A tube. Variable vacuum capa-citors are used to tune the interstage net-work between driver and PA.

20 -kW Class "C" Fria! AmplifierThe power amplifier also uses pi -net-

work circuitry, however, the tuning of thisstage is accomplished by variable inductorsoperating at ground potential. The outputtube is designed for very high power gainwith little drive. Power output is con-trolled by means of a motor -driven vari-able transformer connected in the primary

of the low voltage power supply for thedriver amplifier. This controls the IPA -plate and the PA -screen voltages simul-taneously.

For increased transmitter stability andreliability, a separate grid bias supply isincorporated in the BTF-20E1.,This sup-ply, too, uses semi -conductor rectifiers.


To keep spurious emission at a mini-mum, the transmitter is furnished with a61/8 -inch harmonic filter as standardequipment. The filter consists of a seriesof transmission line elements with a uni-form outer diameter conductor, a steppedinner conductor, and a shunt stub. Theconductors are fabricated of a high-gradecopper alloy. Attenuation of all harmonicradiation above channel limits is accom-plished in an "M -derived" section, and a

series of "constant -K" T -sections. This de-sign provides a broad passband with asharp high -frequency cut-off and excellentattenuation of frequencies above the pass -band.


netically -tripped circuit breakers in addi-tion to overload relays. An interlockedsystem prevents turn -on of plate poweruntil all filaments have heated and theexciter has reached a proper operatingcondition. In addition, a latching relayautomatically re -applies power to thetransmitter once before locking -out in theevent of brief overloads or power inter-ruptions. The overload relays are reset byilluminated push-button switches on thefront panel. Separate tally -light indicatorsare provided for overloads in the driver,power amplifier and low voltage rectifiercircuits.

Simplified Block Diagram of BTF-20E1 FM Transmitter, showing optional stereo and SCA.

LEFT

AUDIO INPUTS

RIGHT OP

SCAAUDIO

INPUT

SCAAUDIO -110INPUT

BTS- I B

STEREOGEN.

B7X -18

SCAGEN.

67 KHz

BT X - I B

SCAGEN.

40 KHz

STEREO

SCA

SCA

DIRECT FM

OSCILLATORAND

BUFFER

A FC

EXCITER

R. F.

AMPLIFIER

OFF-FREQ.

DETECTOR

EXCITERPOWER

SUPPLY

REFERENCECRYSTAL

OSCILLATOR


TO TRANSMITTER

CONTROL CIRCUIT

VARIABLELOW VOLTAGE

SUPPLY

7- 15 WATTS87-MEI MHz

ellDRIVER

7203/4CX250B

DRIVER7203/4CX250B

HIGH VOLTAGESUPPLY

PA

4CXI5000A

TO HARMONICFILTER

AND ANTENNA

PA

BIAS SUPPLY


plied by means of a blower mounted belowthe amplifier stages. A manometer indi-cates the efficiency of the fiber -glass filterat the inlet and heavy sound insulationreduces blower noise to a minimum. Theblower supplies forced air to both the IPAand PA stages.


trols and meters located on a panel justabove the front doors. The push-buttoncontrols include: transmitter on/off, plateon/off, overload reset and power raise/lower. A cabinet disconnect switch, low -voltage circuit -breaker, and filament- andcontrol -circuit breakers are located behind


the left-hand door. The main- and low -power circuit breakers arc located in therectifier unitized cabinet. When servicingthe I1TF-20E1, operation of the "discon-nect" switch removes all voltages from thetransmitter cabinet. Personnel are pro-tected by fully interlocked rear doors, inaddition to interlocked doors on the RFPA cubicle.


provided for each amplifier. One for PA -plate voltage, another for PA -plate cur-rent, and a third for AC -line and filamentvoltage. The remaining three are a reflect-ometer indicating output, a multimeterand VSWR meter. Separate meters areused to measure the forward power andVSWR. The multimeter reads the gridcurrent, the screen current and the screenvoltage of both power tubes. In addition,the exciter has its own self-containedmultimeter. This one provides completeinformation on operating conditions in theexciter.

Ready for Remote ControlRemote control provisions 'are included

in the transmitter and terminals areprovided for use with remote controlunits such as the Type BTR-11B (orBTR-20E) and Automatic Logging Equip-ment. Additional terminals are providedfor remote control of transmitter on/off,plate on/off, raise/lower power, andoverload reset. Remote metering connec-tions in the final amplifier for plate cur-rent, plate voltage, and power output arealso provided.

High -Voltage Power SupplyThe high -voltage power supply is

housed in a unitized cabinet measuring32 inches wide, 23 inches deep and 49inches high. It can be installed at anyconvenient place in the station. The cabi-net houses the high -voltage -plate trans-former, a bank of plug-in semiconductorrectifiers, a line -circuit breaker, a low -power circuit breaker, and the plate con-tactor. Personnel are fully protected fromshock through interlock and groundingswitches.

The rectifier section comprises silicon -junction diodes (with equalizing resistorsand capacitors) in a three-phase, full -wave -bridge circuit. Circuit breakers areused instead of fuses in the transmitteradding to the dependability particularlywhen operating by remote control.

a

UNITIZED HIGH VOLTAGE POWER SUPPLY-With location not tied to the transmitter, theunitized power supply affords many installationand operating economies.

ONLY THREE TUBES BETWEEN EXCITER AND OUTPUT-View showing interior of PA and IPA cabinet with the4CX15000A ceramic tetrode and two IPA tubes below shelf.


Frequency Range 88 to 108 MHzPower Output 20 kW


Frequency Deviation 100% modulation ±75 kHzModulation Capability ±100 kHzCarrier Frequency Stability ±1000 Hz max.Audio Input Impedance Resistive, 600/150 OhmsAudio Input Level-*(100% mod.) +10 ±2 dBmAudio Frequency Response-**(50-15,000 Hz) ±1 dB max.Pre -emphasis Network Time Constant 75 or 50 As, as desired

Harmonic Distortion-***(50-15,000 Hz) 0.5% or lessFM Noise Level (referred to 100% FM mod.) -65 dB max.AM Noise Level (referred to 100% AM mod.) -50 dB max.Subcarrier Input Level (100% mod.) -15 to +10 dBm

adjustableSubcarrier Input Impedance 600/150 Ohms bal.Subcarrier Frequency 20-67 kHz


Sub -to -Main -Channel Crosstalk.... -60 dB referred to ±75 kHzdeviation of the main carrier by a 400 Hz tone. Subchan-nel modulation 100% (±7.5 kHz) by 50-6000 Hz tones.Subcarrier modulated 30% on main carrier.




2-7203/4CX250B

Power Amplifier:1-4CX15000A

Mechanical High -Voltage

Dimensions (overall): Transmitter Power SupplyWidth 481/2" (123 cm) 32" (81.3 cm)Height 77" (195.6 cm) 49" (124.5 cm)Depth 321/2" (82.5 cm) 23" (58.5 cm)

Weight (approx.) 1425 lbs. (646.4 kg.) 1025 lbs. (164.9 kg.)




* Level measured at input terminal J1.** Audio Frequency response referred to 50- or 75 -microsecond pre -emphasis

curve.

*** Distortion includes all harmonics up to 30 kHz and is measuredfollowing a standard 50- or 75 -microsecond de -emphasis network.

t Blowers can be provided for operation at higher altitudes.


12''MIN

32"

IN EXHAUST FAN5000 CFM

12" MINIMUM36 RECOMMENDED

POWER

SUPPLY

LOCATIONOPTIONAL

48',"

TO NCOMINGPOWER SOURCE

T

24- MINIMUM36" RECOMMENDED

O

M 1-561506

32V," -co /- HARMONICFILTER

129.9" LONG

DIRECTION OPTIONAL

f23 63"

TO

ANTENNA-119.

Space -saving floor plan of the BTF-20E1. The separate, unitized power supply may be installed ina basement, attic, closet or other convenient place. (Wire duct and fan shown are not furnished.)

AccessoriesRecommended Spare RF Transistors for Exciter MI -560718

Spare Crystal and Oven(Specify operating frequency) MI -560717

Complete Set of Spare Tubes ES -560609

20 -kW RF Load and Wattmeter (water-cooled) ...M1-19267-L/HType BTR-11B Remote Control System



Type BW-75A FM Frequency andModulation Monitor M1-560735

Type BW-85A FM Stereo Frequency andModulation Monitor M1-560740

Type BW-95A SCA Frequency andModulation Monitor M1-560745


Please specify assigned frequency, power -line frequencyand altitude of installation and select BTE-15A ExciterSystem from the following:

Mono ES -560631



Stereo ES -560634



Commercial Electronic Systems Division BroadcastFront and Cooper Streets, Camden, New Jersey, U.S.A. 08102 111LCil Equipment

catalog B.6535

40 -KW FM Transmitter,

17 El Ea EDE a C) C)

El ED El ED ED CDCM 0 0 ia ;1,- GIC) 0 0

F

Ultra stable-easy to tune Reliable dual RF amplifiers

New solid-state exciter Ready for remote control

Available for mono or stereo with or without SCA3T8

Eye

leve

l Met

ers

and

Sta

tus

Ligh

ts

,tasi

Vita

lE

Dip

lexe

dO

utpu

ts

Com

plet

eC

ircui

tP

rote

ctio

n

=I 19

1M

IMI

NM

Pal

Miri

rn 0

0 0

OIL

IBM

Q 0

01"

412

4

Spa

reE

xcite

rB

uilt-

inR

emot

eC

ontr

ol

0

I

Inst

ant

Sw

itchi

ngto

Spa

reE

xcite

r

I New

Sol

id -

Sta

teF

M E

xcite

r

Air

Flo

wIn

dica

tion

40 -KW Full -Fidelity FM Transmitter, Type BTF-40E1The RCA Type BTF-40E1, 40 kW FM

Broadcast Transmitter is designed for high -power operation in the standard FM band,88-108 MHz and is specifically engineered tomeet and exceed the requirements of multi-plex service transmission.

The transmitter consists of two twenty kWunits driven from a single exciter. The use ofexciter switching and an output diplexingsystem assures continuous operation evenwhen one power amplifier or exciter is re-moved from service for maintenance or repair.The transmitter is housed in two cabinets sep-arated by a control panel and the diplex as-sembly.

The BTF-40E1 employs a new Type BTE-15A Exciter that uses the time -tested and field -proven RCA direct FM system. The circuitsemploy all solid-state components. Their in-herent long -life and cool operation assure

extended reliability and lend themselves par-ticularly to unattended, remote operation.

Because of its wide frequency response andextreme stability, the exciter is ideally suitedfor multiplex and stereo programming, asspecified by the FCC.

The BTF-40E1 uses silicon -rectifier powersupplies for long life and dependability. Forease of tuning, the exciter has a built-in mul-timeter and accessible test points permittingmetering and checking during operation.Built-in manometers can add hundreds ofhours to tube life by indicating air filter effi-ciercy and warning of reduced cooling -air sup-ply over the power tubes.

Frequency response of the transmitter'smain channel is 30 to 15,000 Hz (±1 dBmaximum) and distortion over the same rangeis 0.5 percent or less.

DescriptionThe BTF-40E1 is a diplexed transmit-

ter consisting of two 20E transmittersunited by a mid -combining panel. Thediplexed output combiner, a 3 dB HybridCoupler, and one 6T/8 -inch HarmonicFilter, are external to the cabinets ofthe 40E1.

The combining panel consists of fivesections, the first of which contains thefollowing control and metering functions:six illuminated pushbuttons for operatingthe combined unit on, off, plate on, plateoff, and to indicate transmitter overload,and output line VSWR overload. Alsolocated here are three meters essential foroperation of the 40E1. A "Reject Power"meter is used to indicate power into theair cooled reject load. The second, a"Reflected Output Power Meter," servesto indicate reflected power and to protectthe transmitter from an unusually highVSWR in case of a line or antenna fault.The control can be adjusted to any valueof VSWR. The third meter indicates"Power Output."

The second section in the combiningpanel is used to mount the set pointmodule of the meter -control and to mountthe reflectometer adjustments and con-trols. Below this, a third section containsilluminated switches for Exciter 1 or 2,control circuit line breaker, and a meterindicating reject power in the input balun.The fourth section has a control for ad-justment of the line stretcher used forphasing the input circuits of the combined20E units. The last section is a blankpanel.

In the top of the combiner unit is ablower, thermostatically controlled, sothat in case of failure of either of the20 -kW transmitters, the heat from the10 -kW reject loads will be removed fromthe cabinet. Each air cooled 5 -kW loadis also equipped with a thermo controlledfan for cooling.

The transmitter can be controlled asa 40 -kW unit from the combining cabinetpanel, or as individual 20 -kW transmit-ters from their own control positions. The

BTF-40E1 transmitter, or the individual20 -kW sections can be operated by a re-mote control system.

Relays automatically switch all inputs,that is, stereo and two SCA channels fromone exciter to the other. The primarypower to each exciter is always fed fromthe transmitter that is not shut down.

Mono or StereoThe transmitter features a new exciter

designed for stereo and multiplex. Theexciter, including its self-contained powersupply, is mounted on a single verticalchassis.

Two Stages Follow ExciterFrom the 15 -Watt output of the ex-

citer, only three tubes, two in the IPAand a ceramic-tetrode 4CX-15000A PA,generate the full 20 -kW signal from eachamplifier. A harmonic filter reduces spuri-ous radiation. Vacuum capacitors tunethe IPA plate and PA grid. All PA ad-justments are at ground potential.

Control Panel of one of the diplexed 20 -kW transmitter units. Tally lights and pushbuttoncontrols permit operation of BTF-40E1 even when one power amplifier or exciter is removedfrom service. The large diameter multimeter knobs speed log keeping and minimize error.

New StylingFunctional styling together with fewer

tubes and components has permitted thenew BTF-40E1 transmitter and a controlpanel to be housed in two double -doorcabinets. They employ the new midnightblue and shadow blue finish, set off withaluminum meter panel and trim. Swing -out doors on the front and rear of thecabinet give maximum accessibility. Twoseparate unitized high -voltage suppliesmay , be located anywhere in the FMstation.

New Solid -State FM ExciterExcellent monaural, stereo and SCA



pensated basic on -frequency oscillator isachieved by applying the composite stereoor SCA signals from the BTS-1B andBTX-1B Generators, respectively, to a

Block diagram of the BTF-40E1 FM Transmitter.

BTE- 15AEXCITER

BTE- 15AEXCITER 0

HYBRID RINGPOWER

SPLITTER

REJECTLOAD

BTF-20EIPOWERSUPPLY

BTF 20E1

BTF-20EI

BTF-20 ElPOWERSUPPLY

pair of push-pull varicap diodes which arecoupled to the basic oscillator frequencydetermining resonant circuit. The outputof the basic oscillator is isolated from thefollowing buffer amplifier by a 10 dBresistive attenuator. Thus, the stabilityand modulation characteristics of thebasic direct FM oscillator are not dis-turbed by following RF power amplifiers.

The output of the buffer amplifier, ap-proximately 500 mW, is used to drivethe 15 -Watt, three -stage RF amplifier aswell as the binary divider chain in the

308 HYBRIDCOUPLER

HARMONICFILTER

REJECTLOAD

ANTENNA

LEFT -10AUDIO INPUTS

RIGHT

SCAAUDIO

INPUT

SCAAUDIO

INPUT

BTS-IBSTEREO

GEN.

BTX-1BSCAGEN.

67 KHz

BTX-IBSCAGEN.

41 KHz

STEREO-.SCA

SCA

40KW BTF- 40E1

DIRECT FMOSCILLATOR

AND

BUFFER

AFC

EXCITERR. F.

AMPLIFIER

OFF -FRED.

DETECTOR

EXCITERPOWER

SUPPLY

REFERENCECRYSTAL

OSCILLATOR


TO TRANSMITTER

CONTROL CIRCUIT

VARIABLELOW VOLTAGE

SUPPLY


DRIVER7203/4 CX250B

DRIVER7203/4 CX250 B

PA

-"r"0" 4CXI50 00A

HIGH VOLTAGE

SUPPLY

VTO 40 KWCOMBINER

PA

BIAS SUPPLY

Block diagram of one of the diplexed 20 -kW units of the BTF-40E1 Transmitter, showing optional Stereo and SCA.


AFC circuit. The basic oscillator, bufferamplifier, and AFC circuit are mountedinside a shielded enclosure. The RF poweramplifier is also completely shielded.


for the on -frequency basic oscillator isachieved by taking a sample of the bufferoutput frequency and dividing it by two,14 times. A low -frequency reference crys-

tal operating at 1/1024th of the desiredoutput frequency is divided by two, 4times. Integrated circuits operating in thesaturated mode are used in both binarydividing chains. The outputs from thereference and basic oscillator binary divid-ers are phase compared in a time-sharingIC comparator. The output of the cir-cuit, which represents the AFC error volt-age, is filtered and applied to anotherpair of varicap diodes coupled to the basic

oscillator tuned circuit. Thus, the basicoscillator is phase locked to the 1024thharmonic of the oven controlled referencecrystal.


Two multimters are located on thehinged door in front of the regulatedpower supply section. One of these metersis used to indicate power supply and op-erating voltages within the exciter and15 -Watt RF Amplifier. The second meteris a peak -reading voltmeter that is used toindicate all modulating signal levels.

The RF power output of the BTE-15Acan be continuously adjusted from thefront panel control from 7 to 15 Watts.The primary power is turned on with acircuit breaker. RF output is turned onwith a front panel switch or by jumpingcontacts available on the rear of the unit.The exciter will tolerate load mismatchesfrom short circuit to open circuit for areasonable time without damaging the

output transistor. Another safety featureprevents turning on the 41 kHz SCA sub -carrier when the BTS-1B Stereo Gen-erator is in the stereo mode.

Single -Ended Driver AmplifierI\co simplified, single -ended amplifiers

(operating Class "C") follow the exciterin each 20 -kW unit. The IPA stages con-sist of two ceramic 7203/CX250B tetrodesoperating in parallel, and both final poweramplifiers are Type 4CX15000A tubes.Variable vacuum capacitors are used totune the interstage network between driverand PA.

20 -kW Class "C" Final AmplifierThe power amplifiers also use pi -net-

work circuitry, however, the tuning of

these stages is accomplished by variableinductors operating at ground potential.The output tubes are designed for veryhigh power gain with little drive. Poweroutput is controlled by means of motor -driven variable transformers connected inthe primary of the low voltage power sup-ply for the driver amplifiers. This controlsthe IPA -plate and the PA -screen voltagessimultaneously.

For increased transmitter stability andreliability, separate grid bias supplies areincorporated in the BTF-40E1. These sup-plies also use semi -conductor rectifiers.

Harmonic FilterStandard Equipment

To keep spurious emission at a min-imum, the transmitter is furnished with

111111:11

View showing interior of one of the two identical PA andIPA cabinets with the 4CX15000A ceramic tetrode and twoIPA tubes below shelf.

a 61/8 -inch harmonic filter. The filterconsists of a series of transmission line ele-ments with a uniform outer diameter con-ductor, a stepped inner conductor and ashunt stub. The conductors are fabricatedof a high-grade copper alloy. Attenuationof all harmonic radiation above channellimits is accomplished in an "M -derived"section, and a series of "constant -K"T -sections. This design provides a broadpassband with a sharp high -frequency cut-off and excellent attenuation of frequen-cies above the passband.

Self -ProtectedAgainst Overload

Power circuits are protected by mag-netically -tripped circuit breakers in addi-tion to overload relays. An interlocked

Complete accessibility. Rear view showing one of theamplifiers of the BTF-40E1 revealing the clean, vertical con-struction of PA cavity to left and control panel to right.

system prevents turn -on of plate poweruntil all filaments have heated and theexciter has reached a proper operatingcondition. In addition, a latching relayautomatically re -applies power to thetransmitter once before locking -out in theevent of brief overloads or power inter-ruptions. The overload relays are reset byilluminated push-button switches on thefront panel. Separate tally -light indicatorsare provided for overloads in the driver,power amplifier and low voltage rectifiercircuits.


plied by the use of two blowers mountedbelow the amplifier stages. Manometersindicate the efficiency of the fiber -glassfilter at the inlet and heavy sound insula-tion reduces blower noise to a minimum.The blowers supply forced air to all IPAand PA stages.

Simplified ControlIn addition to the combining control

panel already described, each 20 -kW unithas operating controls and meters locatedon a panel just above the front doors.The push-button controls include: trans-mitter on/off, plate en/off, overload re-set and power raise/lower. A cabinet

disconnect switch, low -voltage circuit -breaker, and filament- and control -circuitbreakers are located behind the left-handdoor. The main- and low -power circuitbreakers are located in the rectifier uni-tized cabinet. When servicing the BTF-40E1, operation of the "disconnect"switch removes all voltages from thetransmitter cabinet. Personnel are pro-tected by fully interlocked rear doors, inaddition to interlocked doors on the RFPA cubicles.


provided for each amplifier. One for PA -plate voltage, another for PA -plate cur-rent, and a third for AC line and filamentvoltage. The remaining three are a re-flectometer indicating output, a multi -meter and VSWR meter. Separate metersare used to measure the forward powerand VSWR. The multimeter reads thegrid current, the screen current and thescreen voltage of both power tubes. Inaddition, the exciter has its own self-contained multimeter, that provides com-plete information on operating conditionsin the exciter.

Ready for Remote ControlRemote control provisions are included

SpecificationsPerformanceType of Emission F3 and F9Frequency Range 88 to 108 MHzPower Output 40 kWOutput Impedance (61/2" O.D. Line) 50 Ohms

Frequency Deviation 100% modulation ±75 kHzModulation Capability ±100 kHzCarrier Frequency Stability ±1000 Hz max.Audio Input Impedance 600/150 Ohms

Audio Input Level-*(100% mod.) +10 ±2 dBmAudio Frequency Response-**(50-15,000 Hz) ±1 dB max.Pre -emphasis Network Time Constant...35 or 50 ps, as desiredHarmonic Distortion-***(50-15,000 Hz) 0.5% or lessFM Noise Level (referred to 100% FM mod.) -65 dB max.AM Noise Level (referred to 100% AM mod.) -50 dB max.Subcarrier Input Level (100% mod.) -15 to +10 dBm

adjustableSubcarrier Input Impedance 600/150 Ohms bal.



Sub -to -Main -Channel) Crosstalk... -60 dB referred to ±75 kHzdeviation of the main carrier by a 400 Hz tone. Subchan-nel modulation 100% (±7.5 kHz) by 50-6000 Hz tones.Subcarrier modulated 30% on main carrier.


4-7203/4CX250BPower Amplifier:

2-4CX15000A

in the transmitter. The Terminals areprovided for use with remote control unitssuch as the BTR-20 Series and BTGSeries Automatic Logging Equipment.Additional terminals are supplied for re-mote control of transmitter on/off, plateon/off, raise/lower power, and overloadreset. Remote metering connections in thefinal amplifier for plate current, platevoltage, and power output are alsoprovided.

High -Voltage Power SupplyThe high -voltage power supplies are

housed in unitized cabinets each meas-uring 32 inches wide, 23 inches deep and49 inches high. They can be installed atany convenient place in the station. Thecabinets house the high -voltage -platetransformers, a bank of plug-in semicon-ductor rectifiers, a line -circuit breaker, alow -power circuit breaker, and the platecontactor. Personnel are fully protectedfrom shock through interlock and ground-ing switches.

The rectifier section comprises silicon -junction diodes (with equalizing resistorsand capacitors) in a three-phase, full -wave -bridge circuit. Circuit breakers areused instead of fuses in the transmitteradding to the dependability, particularlywhen operating by remote control.



Mechanical High -VoltageDimensions (overall): Transmitter Power Supply

Width 1141/4" (288.2 cm) 64" (162.6 cm)Height 77" (195.6 cm) 49" (124.5 cm)Depth 321/2" (82.5 cm) 23" (58.5 cm)

Weight (approx.) 2950 lbs. (1336.4 kg) 2050 lbs. (329.8 kg.)Finish Textured Vinyl in midnight blue and

shadow blue, satin -aluminum trim.Altitude 7500 ft. (2290 m)fAmbient Temperature Range -20° to +45°C

* Level measured at input to pre -emphasis network.** Audio Frequency response referred to 50- or 75 -microsecond pre -emphasis

curve.*** Distortion includes all harmonics up to 30 kHz and is measured following

a standard 50- or 75 -microsecond de -emphasis network."I- Blowers can be provided for operation at higher altitudes.


EXHAUST FAN 6800 CFM(NOT SUPPLIED)

32MIN

----J POWERSUPPLY


I-

0

Izz 112 2

0N

cr

to

-

I

BTF - 20E1 BASIC RACK

30

COMBININGEQUIPMENT

---1POWERSUPPLY


HARMONIC FILTER 6% 0 D.M I -561575 -. TO ANTENNA

ll

BTF - 20E1 BASIC RACK

122.08 (88 TO 108MHz)

NOTE .HARMONIC FILTER MAY BEROTATED ABOUT TRANSMITTEROUTPUT LINE AS REQUIRED

Space -saving floor plan of the BTF-40E1. The separate, unitized power supply may be installedin a basement, attic, closet or other convenient place. (Wire duct and fan shown are not furnished.)

AccessoriesRecommended Spare RF Transistors for Exciter M1-560718Spare Crystal and Oven

(Specify operating frequency) MI -560717Complete Set of Spare Tubes ES -56061320 -kW RF Load and Wattmeter On applicationType BTR-11B Remote Control System



Please specify assigned frequency, power -line frequency,and altitude of installation and also select a Type BTE-15AExciter System from the following:


Type BW-75A Frequency andModulation Monitor MI -560735

Type BW-85A Stereo Frequency andModulation Monitor MI -560740


Mono ES -560631

Mono and one SCA Channe' ES -560632Mono and two SCA Channels ES -560633

Stereo ES -560634



Commercial Electronic Systems Division BroadcastFront and Cooper Streets, Camden, New Jersey, U.S.A. 08102 11011 Equipment

Latest modular design employingsolid-state integrated circuits

"Direct FM" modulation

Excellent frequency response-low distortion and noise

Simplified operation-easy to service

Automatic muting of subcarrier

Fully metered

Off -frequency detector

catalog B.6556

Reil FM Exciter System, Type BTE-15A

DescriptionRCA's new FM Exciter Stereo System

Type BTE-15A, with optional Stereo andSCA generator units provides on -air FMstations with an inexpensive means ofbroadcasting two or more services simul-taneously over their regularly assignedbroadcast channel. Stations can offerbackground music or other services whileretaining presently scheduled FM monoor stereo broadcast programming. Theuse of the equipment for SCA and stereois type accepted by the FCC.

The heart of the system is the newType BTE-15A Exciter, an all solid-stateunit utilizing integrated circuits, and em-ploying RCA's "Direct FM" principle ofoperation. An important feature of thenew exciter system is that it is fullymetered using two meters to measure notonly operating parameters but also mod-ulating signals.

Stereophonic programming requiresthe use of an optional plug-in StereoGenerator, Type BTS-1B. One or twoType BTX-1B Subcarrier Generators

permit one or two additional programchannels to be transmitted along with theregular FM mono program channel. Thisis accomplished by transferring the sub -channel programs into the supersonic fre-quency range and frequency modulatingthe subchannel program on 41-67 kHzsubcarriers. The FM supersonic carriersare then used to modulate the RF carrier.When a BTS-1B Stereo Generator isswitched into the system only one BTX-I B SCA Generator on 67 kHz can beused.

3TB


performance that more than meets in-dustry and FCC standards are achievedby the new RCA modular, solid-state,"Direct FM" exciter. This exciter can besubstituted directly for the BTE-10CExciter in present BTF-1E1 or BTF-5/10/20E FM Transmitters and can beoperated into either short circuit or opencircuit without damage to the outputtransistor.

New design features include a modulardesign that plugs into a frame accommo-dating the Exciter, Power Supply andSwitching, BTS-1B Stereo and one ortwo BTS-1B SCA Generator modules.When operating monaural only, the BTS-1B Stereo Generator is replaced withanother module. The exciter frame is 19inches wide and designed for standardrack mounting. A module extender isprovided to permit easy servicing ofmodules outside the main frame.

CircuitsModulation of the temperature com-

pensated basic on -frequency oscillator isachieved by applying the compositestereo or SCA signals from the BTS-1Band BTX-1B Generators, respectively, toa pair of push-pull varicap diodes whichare coupled to the basic oscillator fre-quency determining resonant circuit. Theoutput of the basic oscillator is isolatedfrom the following buffer amplifier by a10 dB resistive attenuator. Thus, the sta-bility and modulation characteristics ofthe basic direct FM oscillator are notdisturbed by the following RF power am-plifiers.

The output of the buffer amplifier, ap-proximately 500 mW, is used to drive the15 -Watt, three -stage RF amplifier as wellas the binary divider chain in the AFCcircuit. The basic oscillator, buffer am-plifier, and AFC circuit are mounted in-side a shielded enclosure. The RF poweramplifier is also completely shielded.

Automatic frequency control (AFC)for the on -frequency basic oscillator isachieved by taking a sample of the bufferoutput frequency and dividing it by two,14 times. A low -frequency referencecrystal operating at 1/1024th of the de-sired output frequency is also frequencydivided by 16 in a binary chain. Inte-grated circuits operating in the saturatedmode are used in both binary dividingchains. The outputs from the referenceand basic oscillator binary dividers arephase compared in a time-sharing ICcomparator. The output of the circuit,which represents the AFC error voltage,

BTE-15A FM Exciter.

is filtered and applied to another pair ofvaricap diodes coupled to the basic oscil-lator tuned circuit. Thus, the basicoscillator is phase locked to the 1024thharmonic of the oven controlled refer-ence crystal.


Two multimeters are located on thehinged door in front of the regulatedpower supply section. One of thesemeters is used to indicate power supplyand operating voltages within the exciterand 15 -Watt RF Amplifier. The secondmeter is a peak -reading voltmeter that isused to indicate key modulating signals.

The RF power output of the BTE-15Acan be continuously adjusted from thefront panel control from 7 to 15 Watts.The primary power is turned on with acircuit breaker. RF output is turned onwith a front panel switch or by jumpingcontacts available on the rear of the unit.The exciter will tolerate load mis-matches from short circuit to open cir-cuit without damaging the output tran-sistor. Another safety feature preventsturning on the 41 kHz SCA subcarrierwhen the BTS-1B Stereo Generator is inthe stereo mode.

BTS-1B Stereo GeneratorIn the Model BTS-1B Stereo Genera-

tor, latest techniques have been employedto obtain the finest possible stereo opera-tion. The LEFT and RIGHT input chan-nels are identical, each having resistiveinput terminations, isolating transform-

ers, 15 -kHz low-pass filters, and anoperational amplifier for obtaining pre -emphasis. The pre -emphasis is convert-ible from 75 to 50 microseconds in thefield, or can be removed entirely. TheLEFT and RIGHT channels can bematched to within % percent gain differ-ence and degree phase difference from30 to 15,000 Hz, including the 15 -kHzlow-pass filters. These filters are less than0.5 dB down at 15 -kHz, and greater than50 dB down at 19 kHz and above. Thisinsures an absolute minimum of disturb-ance to the pilot carrier and subcarrierregions by the program material.

The pre -emphasized and filtered LEFTand RIGHT audio signals are applied toa switching modulator which alternatelyswitches between the two audio chan-nels. The balanced and symmetrical38 -kHz switching signal is derived froma buffered 38 -kHz output of a bi-stablemultivibrator. The negligible amount ofsecond harmonic (76 kHz) in the 38 kHzswitching signal assures a minimum ofinterference to a 67 kHz SCA channel.The 76 kHz crystal -controlled signaldriving the binary divider assures a fre-quency stable 38 -kHz stereo subcarrier.

The output of the switching modula-tor, along with the sinusoidal pilot (lessthan 1 percent distortion) is applied to aphase linear filter to remove the third andall higher order harmonic components ofthe switching signal. The complete com-posite stereo signal, or a LEFT orRIGHT monaural signal, is selected byrelays and applied to the input of anoperational amplifier. The output of thisamplifier is then applied to the wide -bandinput of the BTE-15A FM Exciter.

Switching between monaural right,monaural left, or stereo may be accom-plished by front panel pushbuttons on

the BTS-1B or by momentary remotecontrol contact closures. The selectedmode is indicated by front panel lamps.Left, Right and Composite program out-puts are also applied to a peak readingmeter on the main frame of the BTE-15A FM Exciter.

BTX-1B SCA GeneratorThe Model BTX-1B SCA Generator,

using all hermetically sealed metal casedintegrated circuits and transistors, is ahigh performance unit designed to oper-ate on either the 41 -kHz or 67 -kHz SCAchannels. The audio input is applied toa resistive terminating pad and then toan isolating transformer before beingamplified. An accessory 5 -kHz low-passfilter must be inserted in the input to pre-vent higher order lower sidebands of the67 -kHz subcarrier from penetrating theupper regions of the stereophonic spec-trum.

The audio amplifier includes an activepre -emphasis network outdating earlierpassive schemes, and may be easilychanged from 75 microsecond to 50 or150 microsecond or adjusted for a flat re-sponse. The audio sensitivity of the BTX-IB is sufficiently high that line amplifiersare not required.

The processed audio input signal isthen applied as modulation to a directFM SCA generator, that includes atemperature compensating circuit for ex-treme frequency stability. A vernier cen-ter frequency control is available on thefront panel.

Following this generator is a seriesdiode muting gate, a buffer amplifier,and a wide -band low-pass filter to re-

BTX-1B SCA Generator.

move subcarrier harmonics. The totalharmonic content of the subcarrier out-put is less than 1 percent and the inci-dental AM is less than 5 percent peakwith 10 percent subcarrier modulation.The output of the low-pass filter is ap-plied to another buffer amplifier andoutput level control for application tothe multiplex input of the BTE-15A FMExciter.

A sample of the pre -emphasized audiois used to drive a peak reading multi -meter on the main frame of the BTE-15A. Automatic muting of the subcarrieris accomplished in the following manner.A portion of the pre -emphasized audiois applied to a variable gain amplifierand using an adjustable time constant,peak detected to operate a Schmitt trig-ger circuit. The output of the Schmitttrigger is shaped with a low-pass filterand used to turn on or off the series diode

muting gate. When audio is applied tothe input of the BTX-1B, the mutingdiode gate is turned on to allow the sub -carrier output to appear. In the absenceof audio, the Schmitt trigger pauses fora selected time interval before turningoff the diode muting gate. The subcar-rier envelope rise and fall times are con-stant and so chosen to minimize "clicksand pops" in a SCA multiplex receiver.The amount of Schmitt trigger delay isadjustable with a front panel control.With this control, subcarrier muting canbe adjusted to occur from 0.5 to 5 sec-onds after the audio input is removed.Two transistors are used to operate frontpanel lamps to indicate the on -off statusof the subcarrier. Also, a front panelswitch provides manual control of thesubcarrier output, or the use of the auto-matic muting feature. The subcarrieralso can be turned on or off remotely.

BTS-1B Stereo Generator.

LEFT

AUDIO INPUTS

RIGHT -

SCAAUDIO -NOINPUT

STEREO

BTS -1 8

STEREO

GEN.

BTX-1BSCAGEN.

67 KHz

SCAAUDIO -INPUT

BT X -I B

SCAGEN.

41 KHz

SCA

SCA

DIRECT FMOSCILLATOR

AND

BUFFER

A FC

EXCITERR. F.

AM.'_1FIER

OFF-FREQ.DETECTOR

REFERENCER1 bTA L

OSCIL LATOR



TO TRANSMITTER

CONTROL CIRCUIT

BTE-15A System.

Rear view of BTS-1BStereo Generator withboard raised to showeasy access to print-ed circuit board.

SpecificationsTYPE BTE-15A EXCITERPerformanceType of Emission F3 -F9

Frequency Range 87-108 MHz

Power Output 15 WattsOutput Impedance (BNC Connector) 50 Ohms

Frequency Deviation for 100% Modulation ±75 kHzModulation Capability ±125 kHzCarrier Frequency Stability ±1000 HzAudio Input ImpedanceAudio Input Level

(100% Modulation) +10 ±2Audio Frequency Response:

50 Hz -10 kHz-pre-emphasis 75 is10 kHz -15 kHz-pre-emphasis 75 .is

600/150 Ohm resistive

dBm at 400 Hz

±0.5 dB max.±1.0 dB max.

Pre -emphasis Network Time Constant 75 or 50 µsec.as desired

Harmonic Distortion (50 Hz -15 kHz) 0.5% max.

FM Noise Level(referred to 100% FM mod. at 400 Hz) -68 dB max.

AM Noise Level (referred to carrier voltage) -60 dB max.


Exciter:Line 240/208 or 117 V, AC, 50/60 Hz, single phaseSlow Voltage Variations ±5%Power Consumption 80 Watts max.

(Including Stereo & SCA)All specifications subject to

Ordering InformationMain Frame for FM Exciter/Stereo/SCA

(Includes integral Power Supplyand Metering) MI -560710

Main Frame for Stereo(Includes integral Power Supply) M1-560711

Main Frame for SCA(Includes integral Power Supply) MI -560720

BTE-15A FM Exciter MI -560712BTS-1B Stereo Generator MI -560713BTX-1B SCA Generator

(Specify SCA Frequency) MI -560714

Mechanica:Overall Dimensions 19" wide, 101/2" high, 9" deepWeight 40 lbs.Maximum Altitude 7500 ft.Ambient Temperature Range -20°C to +60°CFinish Black Background with Aluminum Epoxy Trim

STEREO SUBCARRIER GENERATOR, TYPE BTS-1BPerformancePilot Carrier Stability 19 kHz ±1 HzSubcarrier Suppression -45 dB or betterFrequency Response, 30-10 kHz ±0.5 dB max.Frequency Response, 10 kHz -15 kHz ±1.0 dB max.Pre -emphasis 75 or 50 µsec.Left -Right Channel Separation 35 dB or betterCrosstalk -Stereophonic

(main channel to subchannel) 45 dBCrosstalk (subchannel to main channel) 45 dBHarmonic Distortion

(100% modulation by composite stereo) 1% or less

MechanicalObtains power from BTE-15APlugs into BTE-15A Exciter41 kHz SCA Lockout when using StereoStereo -Mono Remote Switching-Either Left or Right Chan-

nel can be Remotely Switched to give Mono Operation

TYPE BTX-1B SUBCARRIER GENERATORPerformanceType of Modulation FMCenter Frequency Range of Subcarrier 30 kHz to 75 kHzOutput Voltage 4.0 Volts RMS into 10K OhmsFrequency Deviation

(100% subcarrier modulation) ±10% of center frequencyModulation Capability ±15% of center frequencyCarrier Frequency Stability ±0.2%Audio Input Impedance 600 Ohms bal.Audio Input Level

(100% modulation) -15 to +10 dBm adjustableAudio Frequency Response (30 Hz -10 kHz)* ±1 dBtHarmonic Distortion (50 Hz -10 kHz) Less than 1%tFM Noise Level

(referred to 100% modulation) -65 dB max.AM Noise Level (referred to carrier) -50 dB max.

*50 or 150 µs pre -emphasis optionaltWithout low pass filter, measured on

MechanicalPlugs into BTE-15A ExciterObtains Power from BTE-15A Exciter

change without notice.

a wideband detector.

Blank Panel (To replace BTX-1B SCA) M1-560715

Monaural Input Adapter(Replaces BTS-1B Stereo Generator) MI -560716

Oven with Crystal for BTE-15A Exciter(Specify operating Frequency) MI -560717

Recommended Spare RF Transistors MI -560718

Module Extender MI -560719

5 kHz Low Pass Filter (for SCA) MI -560721

Commercial Electronic Systems Division BroadcastFront and Cooper Streets, Camden, New Jersey, U.S.A. 08102 IFILCII Equipment

41111111,11111IN

Fully solid-state circuitry

Outstanding selectivity

Wide dynamic range

Linear phase bandwidth

catalog B.6822PRELIMINARY

Symmetrical (zero -axis) limiting

Wide dynamic range

..di=11111111=1111.11111111111121111113B1111111111111111

110111 Monitor RF Amplifier, Type BW-100B

DescriptionThe BW-100B Monitor RF Amplifier,

an adjunct to the RCA BW-75A Frequen-cy and Modulation Monitor is designedto allow use of the BW-75A at a point,usually the studio, remote from the trans-mitter site. The BW-100B amplifies anoff -air signal (100 µV or greater) to a1 -watt level without modification of theair -signal's characteristics other thanamplitude.

Fully Solid -State CircuitryOnly solid-state circuitry offers the

stability and dependability required of adevice such as the BW-100B. However,the design is enhanced through the useof integrated circuits to reject interferingsignals and provide large dynamic range.

Outstanding SelectivityThe combination of a high level of

selectivity and zero -axis limiters in theamplifier results in the rejection of un-wanted signals (those of other stations inthe area), thereby increasing the useful-ness and accuracy of the monitored para-meters. The BW-100B Amplifier's out-standing selectivity (see Specifications)is the result of a linear, balanced mixersystem that down -converts the off -airsignal to an intermediate frequency(10.7 MHz) amplifier, where it is ampli-fied, filtered and then up -converted backto its precise, original frequency forcoupling to the indicating monitor. Thiscomplete independence of frequencycomes about because the same oscillator-operating at 10.7 MHz above air fre-quency-feeds both mixers simultaneous-ly (see block diagram). Thus, the "input"signal is identical to the "output" signalin every respect except in amplitude and

is stripped of interfering signals. All I -Famplifier tuned circuits are specially de-signed and fabricated for maximumphase linearity and selectivity. Thelinear, balanced mixers are free of spuri-ous responses.

Wide Dynamic RangeAt the threshold of limiting, the BW-

100B requires only 100 µV to deliver a1 -watt signal to the monitor input. Asthe result of a highly linear pre -selectorand a zero -axis limiter, the BW-100Bhandles input signals as large as 0.50volt without overload. This representsa dynamic range of 70 dB. Symmetrical,"zero -axis" limiters maintain constantoutput level adjustable over an inputvariation of 70 dB. The output level isadjustable from zero to 1.0 watt across50 ohms.

2UB

V88-108

MHz

LINEAR,BALANCED

MIXER

10.7

MHz

f + 10.7 MHz

PRECISION BANDPASS

INTEGRATED -CIRCUIT

I -F AMPLIFIER

Specifications

CRYSTALCONTROLLED

OSCILLATOR

10.7

MHz

f + 10,7 MHz

LINEAR,BALANCED

MIXER

88-108

BW-100B Monitor RF Amplifier Block Diagram.

Input Frequency Range 88 to 108 MHzMinimum Input Level (for threshold of limiting) 100 µV

Maximum Input Level 0.5 VInput Impedances 50 to 75 ohmsOutput Impedance 50 ohmsOutput Level Adjustable to 1 wattBandwidth (3 dB points) ±225 kHz


MHz

OUTPUT

AMPLIFIER

f

-9.1 WATT050 S2

Phase Linear Bandwidth ±300 kHzImage Rejection Greater than 80 dBResponse at ±800 kHz 50 dB below that of

center frequencyResponse at ±400 kHz 25 dB below that of

center frequencyPower Requirements 117 V ±10%, 50/60 Hz, 5 W.Dimensions 31/2" (89mm) H, 19" (483mm) W,

101/2" (267mm) D

BW-100B Monitor RF Amplifier(Specify operating frequency) MI -560738


catalog B.6826

RCA

SO

FM MONITOR TYPE BV,

Latest solid state design Total modulation meter respondsaccurately to peak amplitudes

Frort panel modulation calibratorProvides pure signal for companion

Type approved for remote metering Stereo and SCA monitors

RCIi FM Frequency & Mod. Monitor, lype BW-75A

DescriptionThe Type BW-75A FM Frequency

and Modulation Monitor is a wideband,all solid state instrument designed tomeet all the latest requirements for mon-aural monitoring. In addition, it providesa virtually pure, distortionless demodu-lated signal to drive the companionBW-85A Stereo Monitor and the TypeBW-95A SCA Monitor for multiplexmonitoring. It is type approved for re-mote metering.

All frequency and modulation measure-ments are combined in the compact BW-75A that weighs only 14 pounds and isdesigned for mounting in standard mount-ing racks or cabinets. It is designed toaccurately monitor FM transmitters overlong periods of time and operate withoutadjustment week after week.

The BW-75A features a total modula-tion meter that responds accurately tothe peak amplitude of the complex wave-forms encountered in today's program-ming. The peak flasher is completelyindependent of modulation polarity inthat it samples both positive and negativepeaks simultaneously and automaticallyselects and registers the greater ampli-tude if the present level is exceeded.Calibration accuracy can be easilychecked at any time by means of a frontpanel modulation calibrator.

SpecificationsRF Input Sensitivity 0.2 to 10 Volts RMSRF Input Impedance 50 Ohms

RF Frequency Range 88-108 MHz

Deviation Meter Range ±3 kHzModulation Meter Range 133% (100% at 75 kHz)Modulation Meter Accuracy Better than 5% over

entire scalePeak Modulation Indicator 50 to 120%Frequency Response ±0.1 dB, 50-75,000 Hz,

3 dB down at 180 kHzDistortion 0.1% max. 50-75,000 HzStereo Separation 50 dB (at composite output jack)Signal -to -Noise Ratio 75 dB with 75 msec de -emphasisOutputs 4 wide band isolated outputs to drive the

BW-85A and one or more Type BW-95A distortion meteroutput, and monitoring output

Remote Metering Both carrier deviation and modula-tion meters may be remotely metered, 5,000 Ohms externalloop resistance

Size 51/4" high, 19" wide, 101/2" deepWeight 14 lbs.Finish Silver Panel

Ordering InformationType BW-75A FM Frequency

and Modulation Monitor MI -560735

Type BW-85A Stereo Frequency andModulation Monitor (Optional Unit) MI -560740

Type BW-95A SCA Frequency andModulation Monitor (Optional Unit) MI -560745

35B

Commercial Electronic Systems DivisionFront and Cooper Streets, Camden, New Jersey, U.S.A. 08102

RoilBroadcastEquipment

RCA STEREO MONITOR TYPE 8W 85A

Unique phase discriminator allows All solid state satellite unit operatescritical phase adjustments off BW-75A Monitor

Complete stereo monitoring and test functions Convenient front panel meterin

catalog B.6828

RC/1 Stereo Frequency & Mod. Monitor, Type BW-85A

DescriptionThe Type BW-85A Stereo Frequency

and Modulation Monitor is an all solidstate monitor on a compact rack -mountingchassis, designed for measuring all modu-lation characteristics of FM stereo. Itprovides additional facilities for makingthe proper periodic maintenance checksto insure maximum performance fromstereo transmitters, and is type approvedfor remote metering. The monitor is de-signed for satellite operation with thecompanion Type BW-75A Frequency andModulation Monitor, from which it re-ceives a virtually pure, distortionless de-modulated signal.

Complete front panel metering of FMnoise, AM noise and incidental AM, aswell as separation, crosstalk, pilot ampli-tude, and subcarrier suppression, is pro-vided. A unique filter system allows themonitor to be used as an intermodulationanalyzer for measuring stereo distortiondirectly in the frequency range of 5 to15 kHz. Such measurements were pre-viously impossible to the broadcasterwith conventional techniques.

The BW-85A also features a pilotphase regeneration system that utilizes aphase discriminator so that a null readingis obtained with the correct phase, allow-ing the phase to be regenerated within'4 degree. The BW-85A is calibratedwith the modulation calibrator of theBW-75A.

SpecificationsPilot Frequency Meter Range ±3 HzPilot Frequency Meter Accuracy +0.2 Hz (0.001%)Modulation Meter Range 133% to -70 dBModulation Meter Accuracy Better than 5% over

entire scaleFrequency Response (L and R) ±0.5 dB (50-15,000 Hz)Separation 45 dB (50-15,000 Hz) Meter Range -70 dBCrosstalk 60 dB (L+R) to (L-R)

60 dB (L-R) to (L+R)60 dB SCA to (L+R), (L-R)

Outputs:Left & Right Channel Monitoring 600 Ohms, unbalancedLeft & Right Channel Test 10 K, unbalancedDistortion (Either Channel) 0.2%Signal -to -Noise Ratio

(Either Channel) 70 dB with 75 µsec. de -emphasisMonitoring Modes (Modulation Meter

Switched 133% to -70 dB) Left Channel Audio,Right Channel Audio, L+R, L-R, 38 kHz (May be meas-ured with modulating frequencies greater than 5 kHz),19 kHz Pilot Injection (12% full scale), Total Modulation,FM Noise, AM Noise, inc. AM. I

Remote Metering Both pilot frequency and modulationmeters may be remotely metered, 5000 Ohms external loopresistance

Size 51/4" high, 19" wide, 101/2" deepWeight 12 lbs.

Finish Silver Panel

Ordering InformationType BW-85A Stereo Frequency

and Modulation Monitor MI -560740

Type BW-75A FM Frequency andModulation Monitor (Required Basic Unit) M1-560735

Type BW-95A SCA Frequency andModulation Monitor (Optional Unit) MI -560745

Remote Control Panel (accessory for BW-85A) MI -560741

65B

11Commercial Electronic Systems Division

BroadcastFront and Cooper Streets, Camden, New Jersey, U.S.A. 08102 Equipment

CA

Complete SCA monitoring to four channels

SCA modulation calibrator

Three deviation ranges (6, 4 and 2 kHz)

Remote metering facilities

1

catalog B.6830

Wideband discriminator-minimumdistortion and crosstalk

Rack or cabinet mounting

Separate peak flasher for SCA modulationindependent of polarity

AM and incidental AM -noise test functions

RCP SCA Frequency and Modulation Monitor, type BW-95A

DescriptionThe Type BW-95A SCA Frequency

and Modulation Monitor, used in con-junction with the BW-75A FM Frequencyand Modulation Monitor, allows com-plete monitoring and test functions forsubcarrier programming or remote tele-metry applications. Four crystal -switchpositions enable up to four channels to beoperated and tested.

Totally integrated, the solid-state elec-tronics of the BW-95A allow unlimitedSCA frequency selection through a seriesof interchangeable crystals. With the ap-propriate crystals, it is possible to moni-

tor four subcarrier channels through push-button selection. A frequency change issimply a matter of a crystal change.

The BW-95A is a companion equip-ment to the RCA BW-75A and BW-85Amonitors (see Accessories) and incorpo-rates all the latest electronic -design tech-niques. Lightweight and occupying but51/4 inches of rack space, it derives itssignal, a virtually pure, distortionless de-modulated signal from the BW-75AMonitor.

Features of the new BW-95A includethree deviation ranges: Six, four and two

kHz for optimum operation. The six -kHzrange is designed for normal mono oper-ation. The four -kHz range is functionalduring simultaneous stereo and SCA,while the two -kHz range serves telemetryapplications. The 30 -kHz discriminatorbandwidth assures minimum distortionand crosstalk. A separate SCA modula-tion -peak flasher operates independentlyof modulation polarity. A front -panelmodulation calibrator, push-button actu-ated, allows quick check of calibrationaccuracy at any time.

9TB

0

60

50

PEAK MOD.

PERCENT MOD.

90 9070 100

./.°10

120

10- PERCENT

30/ 1 20

100 10

30

40

,,,,,,

-DB

POEOzone

PIMP 070 0110 1.0 wooEt GE

10711( MOOR tab IX. aw. 01(02 00 1100 ligNerk moo moo SCOPE000 D. DEW 040 11041 AY OMR

Note the several pushbutton controls to increase monitor flexibility.Ordinarily these controls are hidden behind the flip -down cover.

SpecificationsFrequency Range Any four SCA frequencies

(switchable) up to 74 kHzDeviation Meter Range ±2 kHzModulation Meter Range 133% (100% at -±-6 kHz,

±4 kHz, or ±2 kHz, switched)Modulation Meter Accuracy Within 5% over

entire scaleMaximum Modulation Frequency 5 kHz at 6 kHz deviationSCA Modulation Calibrator 2 kHzSCA Subcarrier 24 kHz to 74 kHz, four switched

crystal positions. SCA subcarrier and deviation main-tained in the FCC allowable total frequency deviation

SCA Injection Level 133% to 5%Peak Modulation Indicator Follows deviation scale

50 to 120%Frequency Response ±1 dB, 50-5,000 Hz

Crosstalk Rejection 65 dB or greaterCrosstalk Meter Range 70 dB (10 dB steps)Outputs Distortion meter, aural monitor

and oscilloscopeRemote Metering Facility Both meters, separate

circuits, 5000 Ohms external loop resistanceSize 51/4" (133 mm) H, 19" (583 mm) W, 101/2" (267 mm) DWeight 14 lbs. (5.5 kg)Finish Silver Enamel

AccessoriesType BW-75A FM Frequency and Modulation

Monitor (Required Unit) MI -560735

Type BW-85A Stereo Frequency and ModulationMonitor (Optional Unit) MI -560740

Remote Control Panel (for BW-95A) M1-560746

Ordering Information Type BW-95A SCA Frequency and ModulationMonitor (Specify SCA subcarrier frequencies) MI -560745

Commercial Electronic Systems Division BroadcastFront and Cooper Streets, Camden, New Jersey, U.S.A. 08102 RCA Equipment

catalog B.4518

Combines dummy TV antenna andRF power -measurement functions

Easily installed-occupies little space

Power indications givendirectly in Watts

Wide choice of ratings (1.2 to 50 kW)

from 54 to 223 MHz

RCA VHF RF Loads and Wattmeters

DescriptionVHF RF Loads and Wattmeters are

designed for use in measuring the poweroutput of the aural and visual sections ofVHF television transmitters. The loadproperly terminates the output of eitherthe visual or aural transmitter and givesa measurement of the average RF power.It may also be used as a dummy antennafor transmitter tuning. A choice of ratingsis available for any frequency between54 MHz and 223 MHz and for any pow-er level.

The RCA Series of RF Loads andWattmeters consist of a resistor elementfor terminating a transmission line in itscharacteristic impedance, a ThrulineUnit, and a meter for measuring powerdissipated.

The power dissipating section consistsof a resistor unit immersed in a coolantliquid, which is cooled by air in the lowpower units, by tap water in the mediumpower units, and by forced water in highpower loads. In order to prevent exces-sive use of tap water during the time theRF power is at a low level, a water saveris used in most cases. This consists of athermostatically controlled solenoid valvewhich allows the water to flow only whenneeded.

The power measuring section consists

of a short length of transmission line(Thruline), a meter, and a wattmeterelement. A socket is provided on the sideof the transmission -line -coupling sectionto accommodate a calibrated wattmeterelement, which, when coupled to thetransmission line, develops a DC currentproportional to the forward wave voltageacross the load resistor. This current issupplied to a meter calibrated to indi-

cate directly the power dissipated in theload.

The wattmeter element is a reflecto-meter which consists of a coupling loop,a crystal detector, and a filter network.The wattmeter element may be rotated180 degrees in the transmission linehousing. This permits it to indicate theincident power to the load, or the re-flected power from the load.

Accessories

Inner Connector for MI -27791KUngassed Line MI -27791K -4B

Inner Connector for MI -19313 Coaxial Line MI -19313-10

Coupling, Straight MI -191136-8

Coupling, Straight MI -19314C-7

Reducer, 31/2" to 15/a" Coaxial Line MI -19113C-7

Reducer, 61/2" to 31/2"for MI -19113 Transmission Line MI -19314C-13

Water Saver (replacement) MI -27349

6TB

RCA Series of RF Loads and Wattmeters provide necessarytool in measuring aural and visual outputs of VHF Tele-vision Transmitters. Shown above, left to right, are theMI -19267 water-cooled 25 -kW equipment, the MI -561422 air -

Specifications

cooled 5 -kW unit, and the MI -27396 water-cooled 71/2 -kW RFLoad and Wattmeter. Pictured on the front page is the MI -19196 air-cooled 1200 -Watt model. A large 50 -kW RF Load andWattmeter, MI -19191-A, not shown, available on special order.

MI -19196-L/ HFrequency Range 54 to 108 MHz

108 to 216 MHzPower Rating (Ave.) 1200 Watts

(5000 ft. max. elev.)RF Input Impedance 50/51.5 OhmsAC Power Input

M I -561422-L/ H

54 to 108 MHz108 to 216 MHz5 kilowatts

50/51.5 Ohms110 Volts,

50/60 Hzsingle phase

Power Consumption 27 WattsAmbient Air Temperature:

Maximum 45°CMinimum 15°C

Mounting Horizontal

Coolant Capacity 1.7 gallons

Water Required None (air cooled)

Water Connections None

Weight 48 lbs. (22 kg)Dimensions, Overall:

Depth 36" (83.66 cm)Width 6%" (16.19 cm)Height 103/4" (27.3 cm)


MI -27396-L/ H50 to 108 MHz108 to 216 MHz7.5 kilowatts

50/51.5 Ohms

45°C 45°C40°C 15°CHorizontal, vent Floor (fixed or

plug upward portable)2 gallons 4 gallons

dielectric coolantNone 4 gpm (30°C max.

None 1/2" hose

62 lbs. (28.12 kg) 175 lbs. (80 kg)

31-29/32" (81.04 cm)24" (60.96 cm)73/4" (19.69 cm) 20" (50.8 cm)15%" (39.69 cm) 465/8" (118.43 cm)

MI -19267-L/ H50 to 125 MHz100 to 250 MHz25 kilowatts

50/51.5 Ohms115 Volts,

50/60 Hz,single phase

60°C5°CFloor (fixed or

portable)

) 6to 8 gpm (60°C)

Inlet and Outlet3/4" std. pipe

110 lbs. (50 kg)

20" (50.8 cm)24" (60.9 cm)44" (104 cm)

MI -19191 -A -L/ H

54 to 108 MHz108 to 216 MHz50 kilowatts

50/51.5 Ohms115/230 Volts,

50/60 Hz,single phase

1.125 kW

45°C15°CFloor (fixed or

portable)26 gallons

20 gpm (30°C max.)

11/4" hose

1000 lbs. (454 kg)

455/8" (115.89 cm)24%" (62.55 cm)64" (162.56 cm)

300/1200 -Watt RF Load & Wattmeter for VHF Trans-mitter up to 2 -kW picture rating; load is air-cooled and equipped with 33/41", 50/51.5 -Ohm un-flanged fitting MI -19196-L/ H

5 -kW RF Load & Wattmeter for VHF Transmitter upto 6 -kW picture rating; load is air-cooled andequipped with 31/2", 50/51.5 -Ohm unflangedfitting MI-561422-L/H

7.5 -kW RF Load & Wattmeter for VHF Transmitterup to 12.5 -kW picture rating; load is water-cooledand equipped with 31/2", 50/51.5 -Ohm unflangedfitting. Includes MI -27349 Water Saver MI-27396-L/H

25 -kW RF Load & Wattmeter for VHF Transmitterup to 40 -kW picture rating; load is water-cooledand equipped with 61/2", 50/51.5 -Ohm unflangedfitting M I -19267-L/ H

50 -kW RF Load & Wattmeter for VHF Transmitterup to 84 -kW picture rating; load is water-cooledand equipped with 61/2", 50/51.5 -Ohm unflangedfitting M I -19191 -A -L/ H

Commercial Electronic Systems Division BroadcastFront and Cooper Streets, Camden, New Jersey, U.S.A. 08102 1110/1 Equipment

MIN

catalog B.6759

Excellent bandwidth - 1.1:1 VSWRafter field trim

High power handling capability

Lower initial installation andmaintenance costs

Efficient, factory replaceabledeicers

Lower windload

RCP Circularly Polarized FM Antenna, BFC Series

DescriptionThe RCA BFC Series of Circularly

Polarized FM Antennas is designed foruse in monaural, stereo and multiplexFM broadcast service. These antennasprovide a low standing wave ratio over a200 kHz channel providing optimum con-ditions for stereo or multiplex operation.

The BFC Antenna radiates a circularlypolarized wave intended to provide im-proved reception in FM automobile radiosemploying vertical whip antennas and inhome receivers employing built-in or"line cord" antennas. The BFC Antennacan be used to advantage in any appli-

cation which previously required the useof separate vertically and horizontallypolarized antennas of equal power gainand equal power input requirements. Useof the BFC Antenna provides the ad-vantages of lower windload and weightplus reduced complexity and simplifiedinstallation requirements.

Power GainThe new antenna features time proven

sectionalized construction and materialsand can be supplied with as many sec-tions as are required for a given applica-

tion. The BFC Antenna radiates a cir-cularly polarized wave, thus the powergain in the horizontally polarized planeor in the vertically polarized plane is ap-proximately equal to the number of sec-tions divided by two (the number ofequivalent planes of polarization). Whenusing circular polarization in place ofsimple horizontal polarization, the trans-mitter power can be doubled withoutexceeding the licensed horizontal effectiveradiated power since the additionalpower radiated is in other planes ofpolarization; or conversely, for a given

8TB

transmitter power, the antenna gain canbe doubled for the same reason. An ex-ternal power splitter is not required.The antennas are designated BFC-1B,BFC-2B, BFC-3B, etc., depending on thenumber of stacked sections required.

Rugged ConstructionMechanically, the antenna is designed

for rugged service in all types of weatherconditions, and will withstand wind ve-locities up to 110 miles per hour. Radiat-ing elements are made of durablestainless steel that eliminates electrolysisand corrosion when bolted to the copperfeed system. The design is flexible andpermits ease of installation on the side ofan existing tower, or pole mounting ontop of towers or buildings. Mountingbrackets are supplied with antennas forstandard or conventional installations atno extra cost. Custom brackets can besupplied at extra cost for special or un-usual types of installations, The antennacan be supplied with standard poles usingeither pedestal or socket mounts.

De-icing ProvisionsDe-icing equipment is an accessory

item which must be ordered with the an-tenna. The de-icing equipment is recom-mended for most areas and especiallywhere icing and sleet conditions are com-mon. Radomes are available for use inareas where severe conditions exist. Thede-icing equipment is designed to providelong life and trouble free operation andis factory replaceable.

Each bay of a BFC Antenna with de-icers has a current transformer which ismounted either on the pole or on a legof the tower. This transformer, fed with208/240 Volt single phase, delivers 3.0Volts at about 250 Amperes. The outputof this transformer is fed via a heavyteflon insulated wire which has highheat handling capability through each ofthe arms of the antenna and is groundedinternally at the ends of the arms. Thecurrent passing back through the stain-less steel arms heats the arms directly.

Sectionalized ConstructionThe RCA Type BFC Circularly Polar-

ized FM Antenna is of sectionalizedconstruction; each section consisting es-sentially of two crossed semi -circularradiators attached to a supporting frameand a section of 31/8 -inch transmissionline. The antenna input is provided witha 50 Ohm EIA flange for connection toother 31A -inch transmission lines. Adap-tors are available for other transmissionline types and sizes. Standard antennashave power gains from approximately0.5 to 8.0. Special designs are availableon application. An adjustable transformersection is located near the input fitting.A voltage standing wave ratio of 1.1:1or better can be achieved with a mini-mum of field trimming.

Radiation PatternThe horizontally polarized azimuthal

radiation pattern of the BFC antenna isessentially omnidirectional for top mount-ing. The extent of deviation from a cir-

cular pattern for a side mounted array isdependent on type and size of the tower.It is recommended that the array bemounted, if possible, above the top set ofguys on a guyed tower. Where this is notpossible the guys in the immediate areaof the antenna should be broken by insu-lators every 3/2 feet for a distance of atleast 14 feet. In addition, each guy in thevicinity of the antenna should be insu-lated at the point where it connects tothe tower.

Mechanical FeaturesEach section consisting of two crossed

semi -circular radiators is mounted on ashort horizontal section of 15/8 -inch trans-mission line fitted with an insulated cen-tral feed point and supported from the31A -inch feed system. Only one coaxialtransmission line is used to feed all sec-tions of the antenna, and the individualradiating sections are identical mechani-cally and electrically. The radiators areboth shunt fed and mechanically sup-ported by the interconnecting feed sys-tem which consists of modified lengthsof RCA 31/8 -inch rigid coaxial transmis-sion line. The BFC-1B through BFC-7BAntennas terminate mechanically in apressurized top cap with bleed valve anda bottom input flange for connection tothe desired type of transmission line.

The type BFC-8B through BFC-16BAntennas are center fed through a match-ing tee and the lower and top radiatorsterminate mechanically in pressurizedcaps.

H TOP

HCTOP

Mounting Dimensions and Feed Line Locations, BFC Series FM Antennas.(See Table on opposite page)

H SIDE1HC

SIDE

12"MIN.*

15'

31/8" EIA FLANGE(STANDARD)

-CENTER

Pole Mounting Side Mounting End Feed 1-7 Sections Center Feed 8-16 Sections

* Can be made to dimension desired to bring input line to correct support position.

Spe

cific

atio

ns

ELE

CT

RIC

AL

DA

TA

ME

CH

AN

ICA

L

in

DA

TA

at 5

0/33

RC

A

Typ

e

Gai

nP

ower

Rat

ing2

Dim

ensi

onF

eet

Win

dloa

dP

SF

Hor

izon

tal

Ver

tical

Fie

ldIn

tens

ity'

With

Rad

omes

With

out

Rad

omes

Fre

q.3

MH

zH

c T

opH

c S

ide

H T

opH

Sid

eLe

ssW

ithW

ithD

e-ic

ers

De-

Icer

s R

adom

esP

ower

dBF

ield

Pow

erdB

Fie

ldkW

dBk

kWdB

k

885.

0.6

05.

81.

417

819

833

2

BF

C-1

B0.

46-3

.37

0.67

80.

46-3

.37

0.67

893

.210

.010

.04.

06.

0298 10

85.

05.

0.6

0.6

05.

85.

81.

41.

417

817

819

819

833

233

2

8810

.66.

217

.012

.533

737

764

5

BF

C-2

B1.

00

1.0

1.0

01.

013

7.5

20.0

13.0

18.

09.

0398 10

810

.0 9.5

5.6

5.1

15.8

14.9

11.4

10.4

327

319

367

359

635

627

8816

.211

.828

.123

.749

555

595

7

BF

C-3

B1.

51.

761.

231.

51.

761.

2316

8.4

30.0

14.7

712

.010

.79

98 108

15.0

14.1

10.6

9.7

25.8

24.0

21.4

19.5

475

459

535

519

937

921

8821

.717

.339

.334

.865

372

312

69

BF

C-4

B2.

13.

221.

452.

13.

221.

4519

9.2

40.0

16.0

216

.012

.04

9810

820

.018

.615

.614

.235

.933

.131

.428

.662

359

970

367

912

3912

15

8827

.322

.950

.446

.081

091

115

81

BF

C-5

B2.

74.

311.

642.

74.

311.

6422

5.2

40.0

16.0

220

.013

.01

9810

825

.023

.220

.618

.845

.942

.241

.437

.779

176

387

183

915

4115

10

8832

.928

.561

.657

.197

010

9018

74

BF

C-6

B3.

25.

051.

793.

25.

051.

7924

6.0

40.0

16.0

224

.013

.80

98 108

30.0

27.7

25.6

23.3

55.9

51.2

51.4

46.8

920

882

1040

1000

1824

1784

8838

.534

.172

.768

.311

2812

6821

83

BF

C-7

B3.

85.

801.

953.

85.

801.

9526

8.0

40.0

16.0

228

.014

.47

98 108

35.1

32.3

30.7

27.9

65.9

60.3

61.5

55.9

1068

1020

1208

1160

2123

2075

8844

.039

.683

.979

.413

0814

6825

14

BF

C-8

B4.

36.

342.

074.

36.

342.

0728

5.2

40.0

16.0

232

.015

.05

98 108

40.1

36.8

35.7

32.4

75.9

69.4

71.5

68.0

1238

1182

1398

1342

2454

2390

8855

.250

.810

6.2

101.

716

2518

7531

65

BF

C-1

0B5.

57.

402.

355.

57.

402.

3532

2.4

40.0

16.0

240

.016

.02

98 108

50.1

45.9

45.7

41.5

96.0

87.6

91.5

83.2

1535

1483

1735

1663

3075

3003

8866

.462

.012

8.5

124.

019

4221

8237

90

BF

C-1

2B6.

68.

202.

576.

68.

202.

5735

3.2

40.0

16.0

240

.016

.02

98 108

60.1

55.0

55.7

50.6

116.

010

5.8

111.

510

1.3

1832

1744

2072

1984

3680

3592

8877

.573

.115

0.8

146.

422

5825

3844

14

BF

C-1

4B7.

88.

922.

797.

88.

922.

7938

3.9

40.0

16.0

240

.016

.02

9810

870

.164

.165

.759

.713

6.0

124.

013

1.6

119.

521

2820

8824

0823

0442

8442

44

8888

.784

.317

3.1

168.

725

7528

9550

39B

FC

-16B

8.9

9.49

2.98

8.9

9.49

2.98

410.

240

.016

.02

40.0

16.0

298

80.1

75.7

156.

115

1.6

2425

2745

4889

108

73.2

68.8

142.

113

7.7

2205

2625

4669

Effe

ctiv

e fr

ee s

pace

fiel

d in

tens

ity a

t one

mile

in m

V/m

for

one

kilo

wat

t ant

enna

inpu

t pow

er fo

rith

ereq

uiva

lent

hor

izon

tally

pol

ariz

ed c

ompo

nent

or

equi

vale

nt v

ertic

ally

pol

ariz

ed c

ompo

nent

.°

Bas

ed o

n a

40°

C. a

mbi

e t.

Mul

tiply

val

ues

by 0

.8 fo

r 50

° C

. am

bien

t. B

FC

-5 a

nd la

rger

ant

enna

sw

ith h

ighe

r po

wer

inpu

tat

ings

can

be

mad

e av

aila

ble

on a

pplic

atio

n.In

terp

olat

e fo

r in

-bet

wee

n fr

eque

ncie

s.

SpecificationsElectrical:

Frequency range Factory tuned to any channelin the 88 to 108 MHz band

Polarization Circular, clockwise

Power Gain (over dipole)Horizontal Polarization: Approximately equal to half the

number of sections stacked (see table)Vertical Polarization: Approximately equal to half the

number of sections stacked (see table)

Mechanical:Windload 50 psf for flat surfaces:

33 psf for cylindrical surfaces (based on true extremevelocity of 110 mph. (see table of specific antennawind loads)

Section Dimensions:Height 20" (50.80 cm)Diameter 20.7" (52.58 cm)

Feed Point:BFC-1B through BFC-7B Approx. 13' below 4-'1 radiatorBFC-8B through BFC-16B Center fed

Feed point approx. 15' below center

Approximate Weight in Pounds:*Azimuthal Pattern

Horizontal Polarization: Circularity ±1.0 dB in free spaceType DeicersBFC-1B

LessDeicers

76

With

136

WithRadome

118

Vertical Polarization: Circularity ±1.0 dB in free space BFC-2BBFC-3B

137198

257378

221334

VSWR at input (without field trimming) BFC-4BBFC-5B

259320

499620

427530

Top Mounting 1.2:1 or better BFC-6B 381 741 633Side Mounting 1.5:1 or better BFC-7B 442 862 736

BFC-8B 513 993 849VSWR at input (with field trimming) BFC-10B 635 1235 1055

Top or Side Mounting 1.1:1 or better can be achieved BFC-12B 757 1477 1261

over entire 200 kHz channel BFC-14BBFC-16B

8791001

17191961

14671673

Input Connection 31/2", 50 Ohm EIA flange* Weight includes BFC Elements, Feed System to Input &

Power Input Rating See table Mounting Brackets (13" to 18" extension).

OrderingInformationType BFC Circularly Polarized

FM Antenna with standard sup-port brackets for mounting onconventional towers (specify typeor furnish tower drawings).

Order by stock number as

follows:

Less With WithDeicers Deicers Radomes

BFC-1B Single sec. FM antenna ES -561921-A ES -561921-B ES -561921-C

BFC-2B Two sec. FM antenna ES -561922-A ES -561922-B ES -561922-C

BFC-3B Three sec. FM antenna ES -561923-A ES -561923-B ES -561923-C

BFC-4B Four sec. FM antenna ES -561924-A ES -561924-B ES -561924-C

BFC-5B Five sec. FM antenna ES -561925-A ES -561925-B ES -561925-C

BFC-6B Six sec. antenna ES -561926-A ES -561926-B ES -561926-C

BFC-7B Seven sec. FM antenna ES -561927-A ES -561927-B ES -561927-C

BFC-8B Eight sec. FM antenna ES -561928-A ES -561928-B ES -561928-C

BFC-10B Ten sec. FM antenna ES -561929-A ES -561929-B ES -561929-C

BFC-12B Twelve sec. FM antenna ES -561930-A ES -561930-B ES -561930-C

BFC-14B Fourteen sec. FM antenna ES -561931-A ES -561931-B ES -561931-C

BFC-16B Sixteen sec. FM antenna ES -561932-A ES -561932-B ES -561932-C

Commercial Electronic Systems Division BroadcastFront and Cooper Streets, Camden, New Jersey, U.S.A. 08102 l'ILCA Equipment

catalog B.6765

or

Conducts FM power across AM towerbase insulator with minimum effect on AMtower operating impedance

Standard ETA connections-easy to install

Rugged design includesweather and lightning protection

Inserts directly inpressurized FM coaxial transmission line

RCA AM -FM Antenna Isolation Units, Type BAF-15A/16A

DescriptionThe RCA Type BAF-15A and BAF-

16A FM -AM Isolation Units are de-signed to transfer FM power across thebase insulator of an AM antenna towerto feed an FM antenna mounted atop thetower. The units provide isolation of FMand AM signals and efficient operationover the entire FM frequency range.

The BAF-15A Isolation unit is a rugged

pressurized copper section designed tomount directly in 1% -inch FM transmis-sion line between transmitter and an-tenna by means of standard EIA* fittings.It serves as a 10 -kW isolation unit andsecond harmonic filter providing highharmonic attenuation. The BAF-16A Iso-lation unit provides the same functionsand is designed to fit in 3Y8" EIA co-

axial lines fed by transmitters with upto 40 kW FM power. Both units can bemounted to the tower leg by means ofstandard hangers. They are pressurizedfrom the regular FM coaxial line andpermit gas to pass through to thus pres-surize the vertical run of line feeding theantenna. Protection against weather andlightning are design features.

1118

STANDARDTRANSMISSION

LINEHANGERS

(NOT SUPPLIED)

TOWERLEG

Nak.

//

ITOFM ANTENNA

."..-

ANTENNAISOLATIONUNVT

METAL BEAMOR PIPE(NOT SUPPLIED)

1

INSULATED HANGER(SUPPLIED)

TO FMTRANSMITTEROUTPUT

SpecificationsTYPE BAF-15AFrequency Range 88-108 MHzNominal Impedance 50 ohmsMaximum VSWR with 50 ohm Load 1.08Maximum Operating Power FM 10 kWMaximum Tower Base Voltage AM 10 kV peakInsertion Loss Less than 0.1 dBInternal Capacitance to AM 130 pFMaximum Gas Pressure for Pressurizing 30 psigWeight Approximately 55 lbs. (25 kg)Dimensions Diameter 31/2 inches (80mm)

Length 130 inches (3300mm)Connectors Coaxial line (15/8 -inch) EIA* (41mm)2nd Harmonic Rejection 70 dB4th Harmonic Rejection 50 dB6th Harmonic Rejection 30 dB

TYPE BAF-16AFrequency Range 88-108 MHzNominal Impedance 50 ohmsMaximum VSWR with 50 ohm Load 1.08Maximum Operating Power FM 40 kWMaximum Tower Base Voltage AM 14 kVInsertion Loss Less than 0.1 dBInternal Capacitance to AM 130 pFMaximum Gas Pressure for Pressurizing 12 psigWeight Approximately 100 lbs (45 kg)Dimensions Diameter 61/2 inches (156mm)

Length 161 inches (4189mm)Connectors Coaxial line (31/2 -inch) EIA (80mm)2nd Harmonic Rejection 80 dB4th Harmonic Rejection 60 dB6th Harmonic Rejection 40 dB

*Use adapter (MI -19112-62) to connect with RCA 15/8" line.


Type BAF-15A (10 kW) Isolation UnitFor assigned channels between:

88-93 MHz MI -561573-193-98 MHz MI -561573-298-103 MHz M I-561573-3

103-108 MHz MI -561573-4

Type BAF-16A (40 kW) Isolation UnitFor assigned channels between:

88-93 MHz MI -561574-193-98 MHz Mi-561574-298-103 MHz MI -561574-3

103-108 MHz MI -561574-4


Re AN BroadcastEquipment

RCA Commercial Electronic Systems Camden, New Jersey 08102, U.S.A.

Form No. RAD 700116 Printed in U.S.A.

catalog B.6050

50 KW "Ampliphase" AM Transmitter, Type BTA-50J11111111110111111111111

Excellent audio quality Wide range frequency response Only six tubes in transmitting circuits

Proven stability Designed for remote control Over 110 percent positive modulation capability

3TB

Compact in -line construction of BTA-50J showing left to right, left hand poweramplifier, exciter, right hand power amplifier, and rectifier -control cubicle.

DescriptionThe RCA Type BTA-50J AM

Broadcast Transmitter is a completelyair-cooled, 50 -kW phase - to - amplitudemodulated transmitter designed for highfidelity transmission in the standardbroadcast band (535 kHz to 1620 kHz).It provides a signal containing exception-ally low distortion and extended frequen-cy response. Measured response is flatwithin ±3 dB from 35 Hz to 25,000 Hz.The equipment is capable of being mod-ulated over the frequency range of 10 Hzto 30,000 Hz. Frequency response hasbeen extended largely through the elimi-nation of unnecessary transformers in theaudio system as well as improved cir-cuitry.

Low harmonic distortion with negli-gible carrier shift at maximum signaloutput has been achieved in the BTA-50J by selection of adequate power tubetypes and advanced solid state circuits in

the exciter -modulator -drive regulator de-sign throughout the entire equipment.The design features an inherently linearsystem capable of continuous high modu-lation levels impervious to inadvertentovermodulation. For example, the trans-mitter may be modulated 100 percent atany frequency between 30 and 15,000 Hzcontinuously for many hours without det-rimental effects to any of the componentparts. A small amount of overall feed-back is incorporated to provide the ex-ceptional performance. With the feedbackcircuit removed, the BTA-50J will stillmeet the FCC specifications for audio fre-quency response, harmonic distortion andnoise.

Lowest Operating Cost in50 -KW Transmitters

A number of new refinements as wellas time tested features which have proventheir worth are incorporated in RCA's

latest 50 -kW transmitter. Power require-ments arc moderate for the equipment.Power amplifier plate efficiency of theorder of 76 to 80 percent is obtained.Total power consumption for 50 -kW car-rier power will run approximately 94 kW,approximately 100 kW will be requiredfor average levels of modulation, and ap-proximately 130 kW will be required for100 percent modulation.

Fewer major components, as comparedto those required by many 50 -kW trans-mitters, are used in the BTA-50J. In ad-dition to the low cost of operation of thetransmitter a Power Cutback Kit, MI -27688 -B can be added which will permitoperation at 10 kW.

Dual RF ChainsTwo identical RF chains, each develop-

ing a power of 25 kW, are incorporatedin this equipment. Since they are identi-

cal, servicing is made easy by compari-son of the two chains. Components aredirectly interchangeable, which allowssubstitution for comparison purposes. Allcomponents are easily accessible whichresults in a minimum schedule for main-tenance. In addition, fewer replacementparts are required for adequate protectionagainst lost air time should a failure oc-cur. Low power consumption, fewermajor components and a reduced main-tenance schedule make the BTA-50J op-eration cost the lowest in the 50 -kW field.

Remote Control OperationThe transmitter has been designed

with remote control operation in mind.Ready for use with standard RCA re-mote control equipment, all transmittercomponents and wiring are standard inthe equipment for FCC required meter-ing and control facilities. In addition,other optional metering and control fa-cilities may be incorporated by utilizingcomponents and wiring that is suppliedwith the equipment. Details relative to in-corporating remote switching to anauxiliary transmitter, dummy load andauxiliary power supplies can be suppliedaccording to the needs of the individualcustomer.

Lightweight Type 6697Tubes in Final PA

One Type 6697 power amplifier tubeis used in each of the two RF chains.Each amplifier tube is capable of deliver-ing in excess of the normal 25 kW ofmodulated power to the common load.The Type 6697 is rated at 35 kW dissipa-tion and under average modulation con-ditions it is only required to dissipateapproximately 14 kW. Operation of thePA tubes so far below their maximumratings assures the user of long tube life.In addition to providing long life, the6697 is physically small in size and weighsonly 29 pounds. One person, without theaid of mechanical assistance can quicklyand easily replace any tube in the trans-mitter.

One Type 4CX5000A tube is used ineach of the driver stages in the two RFchains. The 4CX5000A is also operatedwell below its maximum ratings and willgive long trouble free service. The onlyother tubes used in the transmitter arethe two 4-250A Intermediate Power Am-plifier tubes. There are also four tubes inthe monitor circuits. These are of thesmall, low cost variety. Tube complementis such that inventory cost for requiredspares is kept at a minimum while ade-

quate protection to the broadcaster ismaintained.

Solid State RectifiersUsed Throughout

All power supplies utilize solid staterectifiers. The plate supplies, bias supplyand low voltage supply use silicon unitswhich are very conservatively rated to as-sure long life. The current rating of theunits is such that any conceivable loadfault is cleared without jeopardizing thediode units. The use of solid state recti-fiers permit the transmitter to operate inambient temperatures as low as -20 de-grees centigrade.

Meets FCC Harmonic SuppressionA completely shielded two section low

pass filter is incorporated in the BTA-50J. It consists of one pi (7r) section andone T section and each inductive serieselement is completely shielded. Twoseries -tuned, shunt -connected traps areused to provide added attenuation of thesecond harmonic.

Transmitter EquipmentType BTA-50J AM Broadcast Trans-

mitter consists of four equipment cabi-nets, two of which house the power am-plifiers, one the exciter unit and the fourthcabinet the rectifier and control unit. Thehigh -voltage reactor is housed in thelower rear compartment of the excitercabinet, and the IHV plate transformerin the lower rear compartment of therectifier and control cabinet.

Each of the four transmitter cabinetsmeasure 44 inches wide by 60 inchesdeep by 84 inches high, and consists of anall aluminum cubicle erected on a weldedsteel base. This cubicle consists of a seriesof panels fabricated and assembled toform a rigid structure. The use of alumi-num eliminates unnecessary weight andprovides excellent shielding to assure ef-fective confinement of spurious energy.Maximum accessibility to all transmittercomponents are afforded by 28 -inch wide,full-length front doors, while rear accessis through two covers attached withquick -disconnect fasteners for easy re-moval.

A center vertical panel separates thecabinet into a front compartment andrear compartment which is further di-vided by a rear horizontal shelf into up-per and lower compartments, giving eachcabinet three basic totally shielded com-partments in which to mount the electri-cal components. The eye -level meters,pilot lights and interlocks, mounted on

eight -inch wide panels flanking each ofthe front doors, are also shielded.

In the rear at the top of each cabinetthere is a built-in wire duct which joinssimilar ducts of the adjacent cabinets toform a continuous duct on the four cabi-nets. This duct has a divider down thecenter on which the interconnection ter-minal boards are mounted. The rear halfof the duct is used for interconnectionwiring while the front half is used forinternal cabinet wiring from the terminalboards. The internal wiring is carriedthrough conduits to its destination in thecabinet thus shielding all power and con-trol wiring from RF fields. Provision is

also made at the top of the cabinets forthe addition of an exhaust air duct.

Power AmplifiersThe left end cabinet and the third cabi-

net from the left end are identical andcontain the final power amplifier stages.The 6697 tube and its grid circuits andpart of the plate circuits are contained inthe front portion of the cabinet. The up-per rear section contains the plate tankcoil, filament transformer and grid leakresistors. The lower rear section containsa low noise blower which cools the 6697tube and its cabinet and the adjacent halfof the exciter cabinet. The two 6697power amplifiers are designed to supplyequal amounts of power to the outputnetwork. Because of the balanced dissipa-tion in the two 6697 PA tubes, less airpressure with resultant lower air flow isrequired for adequate cooling of thepower amplifier cubicles. The lower rearpanel contains an impingement type airfilter for the blower. The PA cabinets areconstructed so that the blowers and filterscan be mounted externally to the cabi-nets, if so desired.

Solid State Exciter -ModulatorLocated directly between the two power

amplifier units is a cabinet that housesin its front section all the solid state cam-ponents from the oscillator through thedriver stages. The separate branches areassembled as mirror images for symmet-rical feed to the PA units at left andright. The rear cabinet section containsthe 50 kW common output circuit, har-monic filter, and reflectometer protectivecircuits.

Above are two vertical sub -compart-ments behind interlocked doors whichcontain the 4-250 and 4CX5000A stages.A meter panel for these stages is locatedat the bottom of these sub -compartments.

alkt

.:114(.1111111114,11#11'11111111,w WOO°

iIIIIIIIIIIIWkilliplift,","I

ot1111I

1 N, isf'''f I ..'1;iiIIII

11f11,0104

,,,,:titt,,Lt.'

Close-up view of one of the dual final power amplifier stages. The newtype 6697 tube together with grid circuits and part of the platecircuits are readily accessible from the front of the transmitter.

The common output capacitors of thetwo PA tanks and the harmonic filter arelocated in the upper rear of the cabinet.Sub -partitions are so arranged in thissection that complete isolation and shield-ing is effected between the various sec-tions of the filter and the outputcapacitor. The lower rear section of thiscabinet contains high voltage filter re-actor and driver DC filament supplies.

Provisions for Standby OperationSpace is provided in the exciter -modu-

lator cabinet for the mounting of asecond exciter -modulator unit. Each ofthe modulator -exciter units are complete

and arranged so that either may be se-lected instantly by means of cutoverswitches. Thus while modulator #1 is inoperation, modulator #2 is in standbycondition. These provisions with the ex-treme reliability designed into the highpower stages essentially provides a second50 -kW transmitter for standby service.

Rectifier and Control UnitThe right hand cabinet contains the

high power rectifiers, low power distribu-tion components, and the majority of thecontrol components. The front of the cab-inet contains the solid state 15 -kV, 5 -kV,and low -voltage bias supplies. Also in-

cluded here are the high voltage ground-ing switches and the 15 -kV filter capaci-tors. The top rear section of the cabinetcontains the control relays, overload re-lays, distribution contactors, and the lowpower distribution circuit breakers. Thedistribution breakers and overload relaysare readily accessible, even though re-cessed so that they will not be damagedor improperly operated. The bottom rearof the cabinet contains the 5 -kV rectifiercomponents including plate transformer.

The PA output circuit is a conventionalpi -network type of tank circuit. Eachtube has its own tank circuit, with a com-mon output shunt element. Each networkis adjusted to provide the proper load tothe power amplifiers.

Drive RegulatorThe drive regulator samples the audio

signal, amplifies it, and applies a desiredvalue to the grids of the second IPA, pro-viding adequate drive to the final ampli-fiers as required by the level of audioinput applied to the equipment. Thistechnique contributes considerably to theoverall linearity during modulation.

During periods of 100 percent modu-lation, the 6697 power amplifier tubes re-quire 15 -kV DC at 7.5 Amperes, which isobtained by using RCA silicon powerrectifiers in a three phase full wave recti-fier circuit. Two other plate voltages,5 -kV and 1 -kV, are provided by separatesilicon supplies. Bias voltages for all tubesare supplied by an additional supply. Thehigh power distribution equipment for thetransmitter consists of an electrically op-erated air circuit breaker, and a manuallyoperated delta-wye switch for the 15 -kVrectifier. The remaining transmitter pow-er is distributed through a manuallyoperated distribution circuit breaker to a460 to 230 -Volt distribution transformerto voltage regulators and thence to thevarious low power distribution circuitbreakers.

Transmitter ControlControl circuits in the BTA-50J con-

tain a number of features which are de-signed to provide maximum flexibility incontrol, protection and operation. Amongthese are choice of single -button or step-by-step starting, automatic timing andsequencing of starting operations, and lo-cation of transmitter faults by a system ofindicators. Protection of the operator isachieved by a system of interlockinggrounding devices; protection of theequipment by conventional relays andcircuit breakers.

SOLID STAT EEXCITER - MODULATOR

DRIVE REGULATOR

AUDIOINPUT

RFAMP.

4-250

RFAMP.

4-250

There are provisions for the protectionof the equipment against transmission lineirregularities and air failure. A reflect-ometer is incorporated in the BTA-50Jthat is sensitive to the changes in voltageto current ratio on the output transmis-sion line to the antenna. A great changein transmitter load acts to remove thecarrier by removing drive momentarily toallow any RF fault to clear. If, however,the fault persists after removing carrierseveral times, the plate power is auto-matically removed.

Control of the transmitter is accom-plished from the front of the rectifier andcontrol cabinet. All necessary wiring toallow control from a remote location orconsole has been provided. Lamps whichshow the status of the transmitter controlcircuits are also mounted on the frontof this cabinet. The control ladder is ar-ranged and interlocked so that the BTA-50J can either be turned on by operatingthe control switches in sequence or byleaving all control switches in the ONposition with the exception of the startswitch, which when operated to the ONposition allows the transmitter to auto-matically come on.

Upper rear of exciter portion of the BTA-50Jshowing the combining and output networks.

I PA

4 CX5000A

I PA

4 CX 5000 A

PA

6697

PA

66 97

SILICONRECTI FIER

POWERSUPPLY

Simplified block diagram of the BTA-50J.

50 KW OUTPUT

MONITOR

AND

PROTECTIVE

CIRCUITS

The two types of overload circuits usedin this transmitter are the current type,instantaneous or time delay, that are con-nected directly in the tube circuit andrectifier ground leads, and the thermalmagnetic circuit breakers connected in theAC power leads used as back. up protec-tion and disconnect switches. The trans-mitter circuitry is arranged so that anoverload will either lock out the platecircuit or allow a single reclosure that willreset if there are no further overloads. Ineither case, when a lockout position hasbeen reached, the transmitter can be re-set by means of an overload reset control.The principal overload relays have indi-cating flags so that even after the over-load has been cleared there is a recordof which overload has operated. Anotherfeature of the control circuit is provisionof indication lamps on each cabinet thatindicate the status of the interlock in thatparticular cabinet.

Installation and LayoutOutstanding features of the BTA-50J

are the small floor space requirementsand ease of installation of the transmitter.In general, the transmitter layout con-sists of three basic parts: the four in -linecabinets which contain the major part ofthe transmitter; the wall mounted switch -gear components; and the main platetransformers. The floor plan illustrates atypical layout of the complete equipment.Elimination of the need for under -floorcable trenches and considerable reductionin external air ducts, simplifies installa-tion and reduces costs.

As shown in the layout, it is desirableto leave a passageway at the right end ofthe frontline cabinets since the circuitbreakers and overload relays are mostaccessible from this end of the transmit-ter. The layout of the front line cabinetsis such that a common exhaust duct canbe used to carry off heated air from thetransmitter.

Wall mounting as shown on the overallfloor plan is suggested to make the BTA-50J most adaptable to existing transmit-ter buildings. The mounting of thesecomponents, however, is not critical as tolocation. They can be mounted in exist-ing power distribution areas if desired.These components include the main platecircuit breaker, a delta-wye switch, adistribution circuit breaker, a 460 to230 -Volt bank of distribution transform-ers, and two single phase open delta con-nected regulators with their controlpanels. These components are wiredthrough conduit and overhead duct-work to the main plate transformers andthe transmitter cabinets.

Front section of the exciter -modulator containing allcomponents from oscillator through the driver stages.

MICRSTEEL COVER

SHEET METAL

LOOK LEVEL

.111 CONNECT 10 STATION GROUNDCARPER DROU. STRAP1 1

DETAIL SHOWINGTYPICAL WIRE DUCT

CONSTRUCTION

\\N

PLATE j RI ATE

TRANSFORMER;

TRANSFORMER :\\

MFTER VOLT METER

DISCONNECT PLATE

MR INLET LOJVRES

PR'll`g4°.,t6FT

L - 3. -TRANSMISSION LINE

DISTRIBUTIONTRANSFORMER

An'NFIYEn7AIR LETER

INLET_,IIPOWER AMPLIFIER CH 1 EXCITER I 1 [POWER AMPLIFIER CH 2

iRECTIFIER & CONTROL

1

-.___

II I

1

IF

.--I J I I 1 I I ]

.

..:-----

t___I

o3;414g;`,Tc7si'

ZEIUILDINCA HEwTINGOUTLET LOCATEDTO SUIT CUSTOMER

rWIRE

DUCTSEE DETAIL

CONSOLE

ID. 3.

4 i SQUARE DUCTSUPPLIED 81 C./STONER

IF REQUIRED

SPEECHINPUT

MONITOREQUIP

\ \ x \` kk\\

Typical floor plan for the BTA-50J Tra-ismitter.

a

SpecificationsGeneralPower Line Requirements:

Line 460 Volts, 50/60 Hertz, 3 phaseCombined Regulation and Variation ....Not more than ±5%

Power Consumption 94 kW (approx.) at zero modulation

Power Consumption ....100 kW (approx.) at average modulation

Power Factor Better than 90%

Crystal Heaters 110 Volts

Type of Emission A3

Power Output (at transmitter terminals) 56 kW (max.)

Frequency Any specified between 535 and 1620 kHz

Frequency Stability Assigned frequency ±5 Hertz

Type Modulation Phase to amplitude

AF Input Impedance 150/600 Ohms

Audio Input Level +10 ±2 dBm

Audio Response ±1.5 dB 30-10,000 Hz

AF Distortion Less than 3% RMS 50-7500 Hz

Noise Level 60 dB below 100% modulation

Carrier Shift Less than 5% neg. 100% modulation

Type Output Unbalanced

Output Impedance 51.5 Ohms or others specified

Spurious Emission (2nd Harmonic and above) ....83 dB down

MechanicalCabinet Size 44" wide, 84" high, 63" deep

(111.8 cm wide, 213.4 cm high, 160 cm deep)

Overall Weight 12,000 lbs. approx. (545 kg)

Maximum Altitude 7500 ft. (2286 m)

Ambient Temperature -20°C +45°C

Maximum Cabinet Weight 3,093 lbs., approx. (1403 kg)

PA Cabinet Weights (each) 953 lbs., approx. (432 kg)

Plate Transformer Weight (total) 820 lbs., approx. (372 kg)

Rectifier Weight 3,093 lbs., approx. (1403 kg)

Exciter Weight 1,241 lbs., approx. (563 kg)

Filter Reactor 570 lbs., approx. (259 kg)

Tuhe ComplementRF Amplifier Section:

2 4-250A2 4CX5000A2 6697

Monitor Circuits:1 1614

2 6AL51 2D21

Intermediate Power AmplifierDriver AmplifierPower Amplifier

Frequency Monitor AmplifierReflectometerThyratron Control

AccessoriesComplete Set of Operating Tubes ES -27222-D

Recommended Spare Set of Tubes ES -27223-D

Type BTR-11B Remote Control Equipment(10 Functions) ES -34280

Type BTR-20D Remote Control Equipment(20 Functions) ES -561415

BTRX-40A-20 Position Extension for BTR-20C Ml-27556

50/10 -kW Cutback Kit for BTA-50JTransmitter M I -27688-B

Dummy Load Schedule of Parts andInstructions ES -34234

BPA-50 Antenna Tuning Unit M I -28903-A/ B

BPA-50 Antenna Tuner (230 Ohms) ES -28903-A

BPA-50 Antenna Tuner (70/51.5 Ohms) ES -28903-B

RF Ammeter (for BPA-50) MI -7147 -Series

Remote RF Pickup Unit (less Meter) M I -28027-C

Remote Antenna Meter MI -7157 -Series

Type BW-11A Frequency Monitor ES -34042

Type BW-66F Modulation Monitor M I -30066-B

Automatic Logging Equipment On Application

Ordering InformationType BTA-50J 50 -kW AM Broadcast Transmitter with two

crystals, remote meter, one set of operating tubes, siliconrectifiers, and one exciter. Does not include antennatuning unit. (Specify operating frequency and outputimpedance) ES -27221-D


4/70 - americanradiohistory.comamericanradiohistory.com/Archive-Catalogs/RCA/RCA-AM-FM... ·...

Documents

Transcript of 4/70 - americanradiohistory.comamericanradiohistory.com/Archive-Catalogs/RCA/RCA-AM-FM... ·...