146_MHz_RECEIVER_PREAMP

Published:2009/7/20 2:56:00 Author:Jessie | From:SeekIC

Uses 146-MHz bandpass crystal filter to suppress front-end in-termodulation-distortion products (IMD) in VHF repeater circuits while providing gain of 6-8 dB to overcome filter insertion loss. Also helps front-end overload problems from strong adjacent-channel amateur signals. Filter response is down 40 dB at ±38 kHz and down over 50 dB beyond 60 kHz from filter center frequency. Filter used is Piezo Technology TM-4133VBP.Input and output for filter should be exactly 50 ohms.-J. M. Hood, Monolithic Crystal Filter Application in Amateur VHF Repeaters, QST, July 1975, p 27-29 and 48.



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