[TenTec] Solving PTO drift

[Vic Klein]

I think that some drift is just in the nature of analog PTO circuits. I
recall trying to get my old Triton compensated to reduce the slight drift
that occurred during use. Many folks have had good results installing the
K4DPK VFO Stabilizer. It auto-compensates to lock the VFO on frequency, but
releases when the frequency is changed quickly as when turning the knob. It
is made to fit into the Corsair and other rigs with just a few connections.
See the Eham reviews.

I actually have one I picked up removed from another rig, complete with
instructions for the Ten Tec 540, 544, and 580 series, as well as for a
Corsair. I intended to use it, but never got that round tuit that I needed.
If you're interested, I'd sell it for $45.

=Vic=
WA4THR
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From: 	Andrew Moore <andrew.nv1b at gmail.com>
Reply-to: 	Discussion of Ten-Tec Equipment <tentec at contesting.com>
Date: 	Sun, 4 Sep 2011 09:02:14 -0400
List-post: 	<tentec at contesting.com">mailto:tentec at contesting.com>

Before I start trying to isolate the source of my Corsair II's PTO drift, I
wonder if anyone has suggestions about possible causes.

I'm making a couple assumptions: 1) the drift is due to temperature
(probably a safe assumption), and 2) since the same amount of drift appears
on both TX and RX, the source is inside the PTO.  It's #2 that I'm not
entirely convinced of, since there are shared TX/RX paths elsewhere.  But
given the mechanical nature and sensitivity of the PTO, it seems to be a
good place to start.

Unfortunately I no longer have a scope here so troubleshooting this will be
a little tough.

I'm tempted to install a small quiet, brushless fan to the rig to stabilize
temperature, but I'd prefer to find the cause of the problem instead of a
workaround.

I don't want to go the DDS route yet on this rig. While I understand the
benefits, I'd like to keep this one as stock as possible.  I love the harsh
sidetone, sticky potentiometers and clunky relays.  I just don't love the
slight drift (and I've had stable Corsairs before, so I know it's possible
to get there).

Thanks,
--Andrew, NV1B