HW-12 rx off-freq question

[Paul Gregory]

Happy weekend, Heathens!

I need a confirmation of a theory as to why my HW-12 listens about 200 cycles
downfrequency from its tx frequency. Seems this difference tracks consistently across
band.

Page 61 of my manual explains that the carrier oscillator, a Colpitts type, uses xtal Y1
to determine "operating frequency to accurately maintain the proper frequency reationship
with the crystal filter bandpass frequency." Several capacitors maintain oscillation.

I understand xtals can migrate off-frequency over time, and there's plenty of that has
elapsed since the rig was assembled. But it that the likely problem? If so, which xtal is
culprit? Or capacitors? Or am I completely off target, here?

-Paul

Sponsored by the City of Tempe 

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