BE FM-20B, 20 KW FM Transmitter

GENERAL SPECIFICATIONS

Power Output: 20 kW (7.5 kW to 22.0 kW)

PA Efficiency: 80% typical

Frequency Range: 87.5 to 108 MHz, tuned to specific operating frequency; exciter programmable In 10 kHz steps

RF Output Impedance: 50 ohm (others on special request)

Output Connector: 3 1/8" EIA flange

VSWR: 1.8:1 maximum. (will operate into higher VSWR with automatic power reduction) Frequency Stability: : +/- 300 Hz, 0° to 50° C

Type of Modulation: Direct frequency modulation of carrier frequency

Modulation Capability: Greater than +/-350 kHz Modulation Indication: Peak reading, color coded, LED display with baseband overmodulation indicator

Exciter: Solid state, 50 watt output, model FX50; incorporating a digitally programmed synthesizer. (10 kHz Increments)

Pre-Emphasis: FCC 75 uS, CCIR 50 uS (where specified), 25 uS (Dolby), or fiat response, selectable

Asynchronous AM SIN Ratio: 55 dB below reference carrier with 100% amplitude modulation at 400 Hz, 75 uS de-emphasis (no FM modulation present)

Synchronous AM SIN Ratio: 50 dB below 20 kW reference carrier with 100% AM modulation at

1 kHz, no de-emphasis (FM modulation +/-75 kHz at 1 kHz)

Tube Complement: 8989/4CX12000A

RF Harmonics: Suppression meets all FCC/DOC requirements and CCIR recommendations

Power Supply Rectifiers: Silicon

ELECTRICAL/MECHANICAL

AC Input Power: 208/240 VAC, Delta or WYE,

60 Hz, three phase (taps for 196 to 252 VAC; other voltages and line frequencies available upon request)

Primary Power Consumption: 30.0 kW (at 0.97 pf) at 20 kW RF output

Overall Efficiency: Typically 67% (AC line Input to RF output)

Size: (Transmitter) 50S' W x 31.5" D x 70" H (128.3 W x 80 D x 177.8 cm)

(Power Supply) 28.5" W x 31.5" D x 70" H

(72.4 W x 80 D x 177.8 H cm)

Weight & Cubage: (Transmitter) 1200 Ibs

(545 kg); 75 cu. ft. (2.1 cu. meters);

(HV Power Supply) 1500 Ibs (681 kg); 45 cu. ft. (1.3 cu. meters)

Altitude: 10,000 ft at 60 Hz (3048 M), 7500 ft at 50 Hz (2286 M)

Ambient Temperature Range: -10° to +50° C

TECHNICAL SPECIFICATIONS

MONAURAL OPERATION

Audio Input Impedance: 600 ohm balanced, resistive, adaptable to other impedances, 60 dB common mode suppression

Audio Input Level: + 10 dBm nominal for

+/-75 kHz deviation at 400 Hz

Audio Frequency Response: :to.5 dB, 30 Hz to 15 kHz, selectable flat; 25, 50, 75 uS pre-emphasis

Total Harmonic Distortion + Noise: 0.02% or less at 400 Hz

SMPTE Intermodulation Distortion: 0,02% or less, 60 Hz/7 kHz 4:1 ratio

CCIF Intermodulation Distortion: 0.02% or less, 15 kHz/14 kHz 1:1 ratio

Transient Intermodulation Distortion: 0,02% or less, sine wave/square wave

FM SIN Ratio: 85 dB below +/-75 kHz deviation at 400 Hz, measured in a 20 Hz to 30 kHz bandwidth with 75 uS de-emphasis

WIDEBAND COMPOSITE OPERATION

Composite Inputs: 3 total, (1) unbalanced and (1) balanced plus front panel test; all

connectors BNC

Balanced Composite Input Impedance:

10K or 50 ohm, nominal, resistive, selectable Unbalanced Composite Input Impedance:

10K ohm, nominal, resistive

Composite Input Level: 3.5 V pop nominal, for

+/-75 kHz deviation

FM SIN Ratio: 85 dB below +/-75 kHz deviation at 400 Hz, measured In a 20 Hz to 30 kHz bandwidth with 75 uS de-emphasis

Composite Total Harmonic Distortion + Noise: 0,02% or less at 400 Hz

Composite SMPTE Intermodulation Distortion: 0.02% or less, 60 Hz/7 kHz 1:1 ratio

Composite CCIF Intermodulation Distortion: 0.02% or less, 15 kHz/14 kHz 1:1 ratio

Composite Transient Intermodulation Distortion: 0.02% or less, sine wave/square wave Composite Amplitude Response: :to.05 dB,

30 Hz to 53 kHz

Composite Phase Response: :to.25 degrees from linear phase, 30 Hz to 53 kHz

Composite Group Delay: 125 nanoseconds Composite Slew Rate: 9 V/microsecond (symmetrical)

Subcarrier Inputs: (3) total, unbalanced, BNC connectors

Subcarrler Input Impedance: 1O0K ohm, nominal, resistive

Subcarrier Input Level: 3,5 V pop, nominal, for

+/-7 ,5 kHz deviation

Subcarrier Amplitude Response: :to.2 dB,

40 to 100 kHz

STEREO OPERATION

Modulation Type: Digitally synthesized stereo, digitally synthesized pilot; no pilot phase adjustment required

Audio Input Impedance: 600 ohm balanced, resistive, floating (adaptable to other impedances)

Audio Input Level: +10 dBm, :t1 dB, for 100% modulation at 400 Hz (adaptable to other input levels)

Audio Input Filters: 15 kHz LPF with delay equalization for minimum overshoot

Frequency Response: :to.5 dB, 30 to 15,000 Hz, 75 uS pre-emphasis (flat, 25 or 50 uS pre­emphasis selectable)

Total Harmonic Distortion + Noise: 0.05% or less at 400 Hz

SMPTE Intermodulation Distortion: 0.05% or less, 60 Hz/7 kHz 4:1' ratio

CCIF Intermodulation Distortion: 0.05% or less, 15 kHz/14kHz 1:1 ratio

Transient Intermodulation Distortion: 0.05% or less, sine wave/square wave

FM SIN Ratio: 82 dB below +/-75 kHz deviation at 400 Hz, measured in a 20 Hz to 30 kHz bandwidth with 75 uS de-emphasis

Stereo Separation: 50 dB or better; 30 to 15,000 Hz (sine wave)

Dynamic Stereo Separation: 50 dB or better; 30 to 15,000 Hz (normal program content)

Linear Crosstalk: Main to Sub/Sub to Main due to amplitude and phase matching of left and right channels, 30 to 15,000 Hz, 45 dB minimum below 100% modulation

Non-Linear Crosstalk: Main to Sub/Sub to Main due to distortion products. 70 dB minimum below 100% modulation

38 kHz Subcarrler Suppression: 80 dB, minimum, below 100% modulation

Pilot Stability: +/- 0.5 Hz, 0° to 50° C

FM 20B system performance is specified using model FX 50 FM Exciter, FS 30 Stereo Generator, and FC 30 SCA Generator where applicable, measured at rated transmitter power of 20 kW into a 50 ohm resistive load.