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Technical Specifications

 

FMi 25T - Technical Specifications

Nov 20, 2017

RF Specs (FM+HD)

Output Power:
Maximum25kW (-20 dB HD signal injection ratio)
ExciterBroadcast Electronics FXi 60 digital FM/HD exciter
PA Efficiency67% or better at rated power
Overall AC Efficiency57% or better at rated power
Frequency:
Range87.5MHz to 108MHz; programmable in 10kHz steps
Stability+/- 150Hz, -10°C to +50°C using high accuracy internal oscillator. 10MHz and 1pps input for synchronization to external (GPS) reference. Automatic switching to internal oscillator if external reference fails.
VSWRRated power into 1.8:1 VSWR, capable of operating into higher VSWR with automatic power reduction; Protected against open and short circuit, all phase angles
RF Harmonics SuppressionInternal harmonic filter meets or exceeds all FCC, IC, CE, CCIR and IEC215 requirements. Meets or exceeds standard NRSC-5A emission limits in all operating modes
Modulation TypeFM digitally synthesized direct to channel, HD digital direct to channel, FM + HD Radio digital direct to channel.
Operation ModesFM + HD Radio or FM Only.
FM Modulation CapabilityGreater than +/-300 kHz
Asynchronous AM S/N Ratio55dB minimum below equivalent 100% amplitude modulation by 400Hz using 75us de-emphasis (no FM modulation present). 65dB typical below equivalent 100% amplitude modulation by 400Hz using 75us de-emphasis (no FM modulation present).
Impedance50 ohm
RegulatoryMeets or exceeds all FCC requirements

Audio Specifications with FXi 60 Digital Exciter

ModesStereo, mono (L+R), L only, R only; remote selectable
Stereo Performance (AES or analog inputs):
Pre-EmphasisSelectable None, 50 or 75 microseconds
Stereo Pilot Tone19kHz ±.03Hz; injection level adjustable 0% to 15% in 0.1% steps; Nominal: 9%; Suppression: 38kHz, 57kHz, 76kHz, and 95kHz; 80dB below ±75kHz deviation.
Stereo Separation65dB or better, 20 to 15kHz
Dynamic Stereo Seperation65dB or better, 20 to 15kHz
Amplitude Response0.1dB, 20Hz to 15kHz
Signal to Noise Ratio87dB or better below 100% modulation at 400Hz; measured in a 20Hz to 22kHz bandwidth with 75us de-emphasis and DIN “A” weighting.
Total Harmonic Distortion<.03%; 20Hz to 15kHz, in bandwidth 20Hz to 22kHz; with 75us de-emphasis.
Intermodulation Distortion:
CCIF<.03% or less (14/15kHz 1:1)
SMPTE<.03%(60 and 7kHz 1:1)
Transient Intermodulation Dist<.03%; (2.96kHz square wave/14kHz sinewave modulation).
Linear Crosstalk90 dB below 100% modulation reference
Non-Linear Crosstalk80 dB below 100% modulation reference
Audio Overshoot<.2dB
Mono Performance (AES or analog input):
Pre-EmphasisSelectable None, 50 or 75 microseconds
FM Signal to Noise Ratio95dB or better below 100% modulation at 400Hz; measured in a 20Hz to 22kHz bandwidth with 75us de-emphasis and DIN “A” weighting.
Amplitude Response±.1dB, referenced to selected pre-emphasis curve
Intermodulation Distortion:
CCIF.03% or less (14/15kHz 1:1)
SMPTE.03% or less (60/7kHz 1:1).
Transient Intermodulation Dist.03% or less (2.96kHz square wave/14kHz sine wave).
Composite Analog Input:
FM Signal to Noise Ratio95dB or better below 100% modulation at 400Hz; measured in a 20Hz to 22kHz bandwidth with 75us de-emphasis and DIN “A” weighting.
Amplitude Response±.01dB, 20Hz to 53kHz; ±.1dB, 53kHz to 100kHz.
Total Harmonic Distortion.005% or less over stereo sub band (10Hz to 53kHz) with 75us de-emphasis.
Intermodulation Distortion:
CCIF.005% or less (14/15kHz 1:1)
SMPTE.005% or less (60/7kHz 1:1)
Transient Intermodulation Dist.005% or less (2.96kHz square wave/14kHz sine wave).
Slew Rate11.8V/us-symmetrical.
Phase Response Variation±.05° from linear phase, 10Hz to 100kHz.
Group Delay Variation±5ns, 22Hz to 53kHz, ±30ns, 53kHz to 100kHz
External SCA, RBDS Performance:
SCA FormatExternally generated, analog FM subcarriers in the range 53-99kHz
SCA Sub-band Amplitude Response±.5dB; 40kHz to 100kHz
SCA Channel FM Signal to Noise Ratio80dB below +6kHz subcarrier deviation at 400Hz with 150us de-empahasis.
Harmonic DistortionLess than .2% in audio pass-band of SCA generator
Intermodulation DistortionSMPTE(60 and 7kHz, 1:1): 0.2% or less, no pre/de-emphasis, SCA generator low-pass filter bypassed.
Crosstalk:
SCA to Stereo80dB below 100% modulation, L or R channel with 75us de-emphasis.
Stereo to SCA80dB below 100% modulation referenced to ±6kHz deviation and 150us de-emphasis.
SCA to SCA80dB below 100% modulation referenced to ±6kHz deviation and 150us de-emphasis per channel
Dual Internal SCA Performance:
Pre-EmphasisSelectable: 150us, 75us, 50us, none.
Amplitude Response±.5dB; 20Hz to 7kHz.
Subcarrier Frequency57kHz to 99kHz.
Signal to Noise Ratio80dB with de-emphasis(150us)
Total Harmonic Distortion.1% 10Hz to 5kHz
SCA Deviation Capability1kHz to 10 kHz; software programmable.
Injection Level2% to 15%, software adjustable in 0.1% increments
Spurious & Harmonic:
2nd HarmonicBetter than 40dB below subcarrier
3rd HarmonicBetter than 45dB below subcarrier
All other components50Hz to 100kHz: better than 80dB below subcarrier.
RBDS Generator (Internal):
Subcarrier Frequency57kHz, ±0.1Hz.
Injection Level2% to 15%, software adjustable.

Mechanical/Physical

Size/Overall Dimensions Installed:
Transmitter56.5” W x 31.5” D x 70” H (143.5 W x 80 D x 177.8 H cm)
Power Supply34.5” W x 31.5” D x 70” H (87.6 W x 80 D x 177.8 H cm)
Weight/Unpacked:
Transmitter1500 lbs. (682 Kg)
Power Supply1750 lbs. (794 Kg)
Cooling Air Requirements:
PA Cabinet1500 CFM
Driver Cabinet500 CFM
High Voltage Power Supplynatural convection
Air OutletAir exhaust at top of cabinet
PrimaryTop of Power Amplifier Cabinet (33” X 30”)
SecondaryTop of Driver (22” X 30”), Power Supply Cabinet (33” X 30”)
Heat Dissipation:
Typical20 kW (68,260 BTU/hr) @ 25 kW RF output
Maximum25 kW (85,325 BTU/hr) @ 25 kW RF output
Air Conditioning Sizing7.1 ton
RF Output Connector3-1/8” EIA flange

Environmental

Ambient Temperature Range+32°F to +122°F (0°C to 50°C)
Altitude7500 ft. (2286 M) @ 50 Hz; 10,000 ft. (3048 M) @ 60 Hz
Humidity0% to 95% Non-Condensing

Electrical

AC Input Voltage:
3-Phase Closed Delta240 VAC (196-252 VAC), 50/60 Hz
3-Phase WYE 3 Wire240 VAC (196-252 VAC), 50/60 Hz
3-Phase WYE 4 Wire400 VAC (339-437 VAC), 50/60 Hz
Disconnect Size300 A per phase, fused disconnect recommended
AC Wire Size400 KCMIL copper, THHN or equivalent
Current Draw @ 25 kW155 A per phase average (actual determined by line voltage, carrier frequency, etc.)
AC Power Consumption:
Typical @ 25 kW RF Output Power45 kW
Maximum @ 25 kW RF Output Power50 kW
Power Factor0.94 or better at full load
Surge ProtectionExternal surge suppressor (supplied by customer)

All Specifications Subject to Change Without Notice


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