ATV_DOWNCONVERTER_FOR_902_TO_928_MHz

Published:2009/6/18 4:51:00 Author:May | From:SeekIC

This clownconverter converts ATV signals in the 902- to 928-MHz range to a 61.26- or 67.25-MHz IF output frequency (CH 3 or CH 4) to enable reception of these signals on a standard VHF TV receiver or monitor. It features a low-noise RF amp feeding a Schottky diode double-balanced mixer, a tunable LO and one IF preamp stage. The RF amplifier is a low-noise dual-gate GASFET that is followed by a sec-ond RE stage using an MMIC. Five tuned circuits are used in the RE amplifier. This feeds a packaged Schottlqr diode mixer assembly for better dynamic range and reduced susceptibility to intermodulation and strong signal areas. The on-board local oscillator (LO) is voltage tuned and if desired can be set up for remote tuning. Ail necessary circuitry for remote tuning is on board for coax dc and IF feed. This enables the clownconverter to be mast mounted to get around feedline losses generally associated with this frequency range. No separate dc feed is necessary because the coax (RG59/U recommended) carries dc power, tuning voltage, and IF signal. A dc block is used at the receiver for the purpose of separating dc voltage supply and the tuningvoltage. This allows a cable run of several hundred feet, if needed.By using this clownconverter and transmitter, a physically small915-MHz ATV station or even a video HT can be constructed because both units are each 2.50 x 4.00 inches x 1.00 high, and can be stacked together. A complete kit of parts, including PC board is available from North Country Radio, P.O. Box 53, Wykagyl Station, New Rochelle, NY 10804-0053A.



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