Belar RFA-4 Frequency Agile FM RF Amplifier




The Belar RFA-4 Frequency Agile FM RF Amplifier is a microprocessor controlled, tunable RF amplifier designed for use with Belar’s complete line of FM monitors, including the FMM-1 series, the FMM-2 series, and The Wizard. It features 10 memory locations for one-button access to 10 stations with call letters. Direct dial of any standard FM frequency is also possible, and UP/DOWN buttons are included. The station’s call letters can be programmed into the display with the frequency for quick and easy reference. A sophisticated, multistage filter ensures the highest possible performance.

When used with The Wizard Precision Digital FM Modulation Analyzer (Model FMMA-1), the RFA-4 can be operated completely remotely, via an IBM compatible PC and 2400-baud modems. Any preset can be accessed, and any station can be dialed in directly.

Local Oscillator and 10.7 MHz IF outputs are provided for use with the Belar FMM-4A Frequency Monitor for easy and convenient off-air frequency measurement.



  • 10 memory presets with programmable call letters
  • Direct dial of any standard FM frequency in 50 kHz increments
  • Non-volatile memory for presets, calls
  • Input Attenuator: 0, 6, 12, 18 dB, switched
  • Automatic Gain Control (AGC)
  • Can be operated remotely (with The Wizard and optional Interface Module)

Technical Specification

Technical Specification

RF Input Sensitivity:
100 uv

Signal-to-Noise Ratio:
100 uV input 75 dB
500 uv input 85 dB

RF Input Impedance:
75 ohms, BNC Connector

Input Attenuator:
0, 6, 12, 18 dB

RF Frequency Range:
87.75 – 107.95 MHz in 50 kHz increments

650 kHz IF, 10.7 MHz IF, 98.45 MHz to 118.65 MHz LO

Capture Ratio:
1.5 dB


Alternate Channel:
27 dB

3rd Adjacent Channel:
46 dB

Harmonic Distortion:
< 0.03% @ 1 kHz, 75 kHz deviation Separation with FMM-2 or Wizard Demod:
1 kHz 65 dB, 15 kHz 55 dB

1 EIA Rack Unit 1.75″H x 10.5″D x 19″W

Power Requirements:
110/220 VAC, 50/60 Hz

Power Consumption:
20 VA

Shipping Weight:
11 lbs

© Copyright 2000 Belar Electronics Laboratory, Inc. All rights reserved.

New in 2015 – 3 Year Factory Warrant to all Belar Products

Product Resources

Product Resources

Belar RFA-4 Manual

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