FM-25K
TRANSMITTER SPECIFICATIONS

POWER OUTPUT: 10 kW to 25 kW.
FREQUENCY RANGE: 87.5 to 108 MHz, tuned to
specified operating frequency. Exciter
programmable in 50 kHz increments.
RF OUTPUT IMPEDANCE: 50 ohms.
OUTPUT TERMINATION: 3 1/8 EIA flange.
FREQUENCY STABILITY: ±300 Hz 0°- to 45°C TCXO.
TYPE OF MODULATION: Direct Carrier Frequency
Modulation.
MODULATION CAPABILITY: ±100 kHz.
AC INPUT POWER: 208/240 V, 3-phase, 50/60 Hz and
360/415V, 3 phase, 50/60 Hz, 4-wire. Power
consumption: 40 kW typical.
RF HARMONICS: Suppression meets all FCC
requirements.
ALTITUDE: 10,000 feet (3048 meters).
AMBIENT TEMPERATURE RANGE: -20°C to +5O°C . Maximum temperature 50°C @ sea level, decreasing
2°C per 1000 feet (305 meters) to 30°C maximum at 10,000 feet (3048 meters). MAXIMUM VSWR: 1.7 to 1.
SIZE: Transmitter cabinet, 34.6" W (87.8
cm) x 71.7" H (182.1 cm) x 31.0" D (78.7 cm).
HV power supply cabinet: 48.0" W (121.9 cm) x 60.2" H (152.9 cm) x 24.2" D (61.5 cm).
FINISH: White, blue and black.
WEIGHT & CUBAGE: (Estimated) Export: 3000 lbs.(1361
kg). Domestic: 2700 lbs. (1225 kg). Cubage: 150 cubic feet.
WIDEBAND COMPOSITE OPERATION
COMPOSITE INPUT: One balanced floating input.
COMPOSITE INPUT IMPEDANCE: 2000 ohms resistive.
COMPOSITE INPUT CONNECTOR: Female BNC.
COMPOSITE INPUT LEVEL: 1.0 volt RMS nominal for ±75 kHz
deviation.
EXTERNAL SCA GENERATOR INPUTS: Up to two unbalanced inputs
(optional).
COMPOSITE FM SIGNAL TO NOISE: 80 dB below 100% modulation
(reference 400 Hz @ ±75 kHz deviation with 75 microsecond de-emphasis, 20 Hz to 200 kHz
bandwidth). COMPOSITE HARMONIC DISTORTION:
.08%.
COMPOSITE INTERMODULATION DISTORTION: .02% (60 Hz/ 7 kHz 1: 1 tone pairs).
COMPOSITE CCIF INTERMODULATION
DISTORTION: All
distortion products below 80 dB (reference 14 kHz/15 kHz test tone pair).
COMPOSITE AMPLITUDE RESPONSE: ±0.1 dB, 30 Hz-53 kHz.
ASYNCHRONOUS AM SIGNAL TO NOISE: 55 dB below reference carrier AM
modulation 100% output power.
MONAURAL OPERATION
AUDIO INPUT IMPEDANCE: 600 ohms, balanced, resistive,
transformerless, adaptable to other impedances.
INPUT FILTER: Controlled response low pass filter,
defeatable.
AUDIO INPUT LEVEL: +10 dBm ±1 dB for 100%
modulation at 400 Hz.
AUDIO FREQUENCY RESPONSE: Standard 75 microsecond FCC
pre-emphasis curve ±0.5 dB, 30 Hz-15 kHz. Selectable:
flat, 25 or 50 microsecond pre-emphasis.
HARMONIC DISTORTION: 0. 15%, 30 Hz to 15 kHz
de-emphasized.
INTERMODULATION DISTORTION: 0. 1 %, 60 Hz/7 kHz test tone pair,
4:1 ratio.
CCIF INTERMODULATION DISTORTION: All distortion products down 70 dB
(reference 14 kHz/15 kHz test tone pair).
FM SIGNAL TO NOISE RATIO: 80 dB below 100% modulation
(reference 400 Hz @ ±75 kHz deviation, measured 20 Hz to 200 kHz bandwidth, 75
microsecond de-emphasis).
STEREO OPERATION
TYPE OF MODULATION: Digitally Synthesized
Modulation (DSM).
AUDIO INPUT IMPEDANCE: Left and right channels: 600 ohms,
balanced, resistive, transformerless, adaptable to other impedances.
AUDIO INPUT LEVEL: +10 dBm, ±1 dB for 100%
modulation.
AUDIO FREQUENCY RESPONSE:
(Left and right) standard 75
microsecond FCC pre-emphasis curve ±0.5 dB, 30 Hz-15 kHz.
Selectable: flat, 25 or 50 microsecond pre-emphasis.
INPUT FILTERING: 15 kHz low pass filter, 45 dB
rejection at 19 kHz.
OVERSHOOT PROTECTION: Harris patented Dynamic Transient
Response (DTR) filter. Defeatable for test
purposes.
AUDIO TRANSIENT RESPONSE: 2% maximum overshoot beyond steady
state.
HARMONIC DISTORTION: (Left or right) 0.2% or less,
30-15,000 Hz.
INTERMODULATION DISTORTION: (Left or right) 0.12% 60 Hz/ 7 kHz
test tone pair, 4:1 ratio.
CCIF INTERMODULATION DISTORTION: (Left or right) all distortion
products down 75 dB (reference 14 kHz/15 kHz test tone pair).
STEREO SEPARATION: 50 dB, 30 Hz-15 kHz; typically
60 dB at midband frequencies.
DYNAMIC STEREO SEPARATION: 48 dB under normal programming
conditions.
LINEAR CROSSTALK: - 50 dB.
NON-LINEARCROSSTALK: -6O dB.
76 kHz SUPPRESSION: - 68 dB.
38 kHz SUPPRESSION: - 73 dB.
FM NOISE: (Left or right) 72 dB minimum below 100%
modulation. Reference: 400 Hz, 75 microsecond
de-emphasis, ±75 kHz deviation, measured 30 Hz to 15 kHz bandwidth.
PILOT OSCILLATOR: Crystal controlled.
PILOT PHASE: Harris patented automatic pilot
phasing circuit. PILOT STABILITY: 19 kHz ±1
Hz 0° to 50°C.
OPERATIONAL MODES: Stereo, mono (left and right),
mono (left), mono (right)-remoteable.
SCA OPERATION
MODULATION: Direct FM.
FREQUENCY OF OPERATION: 41 or 67 kHz
programmable, any frequency between 25 and 75 kHz on special order. FREQUENCY STABILITY: ± 500 Hz.
MODULATION CAPABILITY: ± 7.5 kHz.
AUDIO FREQUENCY RESPONSE: 41 kHz and 67 kHz AC coupled input,
150 microsecond pre-emphasis ±1 dB, standard. Selectable
flat, 50 or 75 microsecond pre-emphasis. DC
coupled input: No pre-emphasis: DC to 4 kHz ±0.5
dB.
AUDIO INPUT IMPEDANCE: 600 ohms balanced (AC coupled). Also 2000 ohms DC coupled unbalanced input through
rear BNC connector.
AC INPUT LEVEL: +10 dBm, ±1 dB for 100% modulation at 400 Hz @ 600 ohms.
DC INPUT LEVEL: 1.0 volt peak for 5 kHz deviation.
INPUT FILTERING: Programmable LPF, 4.5 kHz
standard. 3 kHz, 5 kHz, 7.5 kHz selectable. Low
pass filter defeatable. HARMONIC DISTORTION:
0.5%,30-4,500 Hz ±5 kHz deviation
INTERMODULATION DISTORTION: 1%, 60 Hz/7 kHz, 1: 1 ratio (audio
low pass filter and pre-emphasis bypassed).
FM NOISE: (Main channel not modulated) -63 dB
(reference: 100% modulation = ± 5 kHz deviation at 400 Hz).
CROSSTALK: (SCA to main or stereo sub-channel) -60
dB or better.
CROSSTALK:
(Main or stereo sub-channel to SCA) 57 dB below
±5 kHz deviation of SCA with mono or stereo channels modulated by frequencies 30
Hz-15 kHz, SCA demodulated with 150 microsecond de-emphasis.
CROSSTALK: SCA to SCA (41 kHz/67 kHz) - 50 dB
demodulated with 150 microsecond de-emphasis.
AUTOMATIC MUTE LEVEL:
Variable from O to -3O dBm.
MUTE DELAY: Adjustable 0.5 to 20 seconds.
INJECTION LEVEL: 1% to 30% of composite level
(adjustable).