MODULATION_MONlTOR

Published:2009/6/28 22:18:00 Author:May | From:SeekIC

Provides off-the-air monitoring of RF signals up to 200 MHz by rectified detection of AM signals and by slope detection of FM signals. Can also be used as signal tracer, audio amplifier, orhidden-transmitter locator. High-gain audio amplifier has low-noise cascode input stage and output stage driving headphone or Ioudspeaker. S1 selects RF signals detected by D1 or AF applied to J2. L1 is 4 tums No. 18 for monitoring 75-150 MHz. Will also monitor VHF transmissions from pilot to ground stations while in commercial aircraft, using 24-inch wire antenna near window and earphone. Passive-type receiver is safe in aircraft because it has no oscillators that could interfere with navigation equipment. -W. F. Spli-chal, Jr., Sensitive Modulation Monitor, CQ, Jan. 1973, p 59-61.



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