2255 - 2455 kHz local oscillator (VFO)

This 2 transistor based covers the whole 160m bandwidth (frequencies between 1800 and 2000 kHz). The intermediary frequency is, of course, 455kHz.
The oscillator has good stability, with circuit noise at least 90 dB below fundamental output. Amplifier Q14 provides required +7 dBm for injection into the balanced mixer of the receiver.


C2 - double-bearing variable capacitor, 50 pF
C3 - miniature 30 pF air variable capacitor
CR1 - high speed switching diode, silicon type 1N914A
L18 - 17 to 41 uH slug-tuned inductor, Qu of 175 (J.W. Miller 43A335CBI in Miller S-74 shield can)
L19 - 10 to 18.7 uH slug-tuned pc-board inductor (J.W. Miller 70F103AI)
VR2 - 8.6V, 1W Zener diode
Q13 - MPF102
Q14 - 2N2222A

This 160m VFO schematic is a two-part article in D. DeMaw, His Eminence-the Receiver, QST, Part 1-June 1976, p 27-30 (Part 2-July 1976, p 14-17)


References: www.seekic.com

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