6545_6845_MHz_VFO

Published:2009/7/13 22:03:00 Author:May | From:SeekIC

Covers 40-meter amateur band of transceiver for SSB and CW with stable incremental tuning circuit using Motorola MV1654 varactor diode CR3. Tuner permits up to 10-kHz offset above or below VFO frequency. Varactor control voltage is set by offset tuning control R3. R4 compensates for differences in varactors and adjusts VFO for zero off-set. Output buffering is provided by Q6 and Q7, with 07 also serving as power amplifier for balanced mixer used in companion exciter of transmitter. S2 activates receiver offset. Relay K1 automatically turns off offset when receiver is in transmit or standby mode, Offset feature is needed only if there is frequency difference between transmitted and received signals. L4 has 5 turns No. 22 on 1/2-inch slug-tuned ceramic form.-W. J. Weiser, Simple SSB Transmitter and Receiver for 40 Meters, Ham Radio, March 1974, p 6-20.



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