Hi everyone,
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.
Dan Newby
WD4LUR
newbyd@ipix.com
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