[R-390] Calibration issue

[Jon]

Hello Group,

I'm in the process of going thru electrical calibration on my R390A. I
noticed a couple of things when I turned on the calibration signal. After I
zero adjusted it to achieve zero beat frequency I can basically do two
things in which I would have to zero beat it again. First by just going +/-
say 50khz (or maybe even less) around the calibration point, in this case
09.000  I would have to re zero and there would be a good tone not just a
little off beat. The other observation is by just sitting on the calibration
mark and returning after about 15 minutes it again would be off. However not
as bad. BTW the receiver has been warmed up for at least 2 hours in advance.
I guess I'm trying to pin down whether the BFO or PTO is drifting or maybe
the 100Khz signal is off.

Thanks,
Jon, KB1Dc