Hi Garey,
I will have to try what you are suggesting and see if the instability is
localized to 40m (where I am mostly), or is on the other bands. Will
let you know.
As to how I am determining it, I am mostly on digital modes (mainly
PSK31) and I am seeing the jumps when viewing the digital signal traces
on the computer display, as well as hearing the freq shifts (I'm a
musician in my spare time, so I am well tuned to audio frequency changes).
Thanks,
Loren - WA3WZR
On 6/2/2010 9:26 AM, Garey Barrell wrote:
Loren -
It's highly unlikely that BOTH PTOs would develop the "jitters" at the
same time, so the problem is probably elsewhere. Does this occur on
ALL bands, in particular both 80M and 40M for example?
IF it appears on BOTH 80M and 40M, then my next suspect would be the
contacts of relay K2. Does it appear on BOTH SSB and CW, or one or
the other?
V1, the Band Oscillator tube, would be the next suspect, IF the
problem appears on 40M, but NOT on 80M or 20M.
Lastly, how are you determining the instability? If you're listening
to the Calibrator, confirm that it's NOT the Calibrator that is jittery!
Let us know!!
73, Garey - K4OAH
Glen Allen, VA
Drake 2-B, 4-B, C-Line& TR-4/C Service Supplement CDs
<www.k4oah.com>
Loren McCullough wrote:
What factors could contribute to frequency instability EXTERNAL to
the PTO?
My TR-4C has just developed a "jittery" frequency, jumping back and
forth around center freq by as much as 50Hz. I know someone (if not
many) will refer me to the excellent articles on PTO rebuilds, but
before someone does, let me say that I have rebuilt my internal PTO
last year and it has been working flawlessly since then. I believe
this is external to the PTO because I am seeing the same instability
on both the internal PTO (rebuilt last year as stated previously) and
also on the RV-4C PTO (factory original, but has always been stable,
other than a heat induced drift issue mentioned in another thread).
Is this a Oscillator tube going bad, or some other component in the
freq. chain?
Thanks,
Loren - WA3WZR
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