3955_4455_MHz_VFO

Published:2009/7/2 7:12:00 Author:May | From:SeekIC

Basic Colpitts LC oscillator designed for 80-meter receivel wiith 455-kHz IF uses zener in supply line to minimize frequncy drift. Emitter-follower buffer contributes to stability by isolating oscillator frommlxer Low-pass filter C13-L2-C14 attenuates harmonic currents developed in Q3 and Q4. L1 is Miller 4503 1.7-2.7 μH variable inductor. L2 is 48 turns No.30 enamel closewound on 1/4-inch wood dowel or polystyrene rod. Main tuning capacitor C10 can be 365-pF unit with six of rear rotor plates removed.-D. DeMaw and L. McCoy, Learning to Work with Semiconductors, QST, June 1974, p 18-22 and 72.



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