I have noticed some of the postings about Corair II drift and thought I'd
let you know something I found out about the one I owned at one time.
I found that about half the drift I saw on the read out, was caused by the
readout and not actual PTO drift. You can verify that by turning the rig
on, measuring the tx frequency on a already warmed up high quality
frequency counter. Then repeating this about every 5 minutes over a hour. I
found that the readout was tracking the PTO frequency.
If you look at the readout board, you will find a trimmer for the reference
osc that is VERY close to a IC that gets pretty warm. If I remember
correctly it was the PROM. On top of that the trimmer was a cheap plastic
one. I simply replaced it with a high quality ceramic trimmer and
re-calibrated it. I was suprised to see how much it actually helped the
readout track the operating frequency.
Just thought you might like to try that. It was very simple to do.
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