John,
Is the VFO stabilizer a frequency reference/PLL based system or is it a
temperature compensation type unit? I'd have to dig it out but I recall
seeing a system (possibly in ARRL Solid State Design?) which used a couple of
thermistors in a bridge circuit to drive a tuning diode and compensate for
VFO/PTO drift that way. That type of compensation shouldn't cause a problem
with an offset or RIT.
If it's the former, you might take a look at the schematics for the 555 Scout
for ideas because I think it used a frequency reference/PLL type of system to
control the drift of the PTO.
73, Al
On Wed June 25 2014 11:00:07 am John Farler wrote:
>
> A friend has an old model vfo stabilizer for PTO type VFO's
> like the one in the old TenTecs. He put it on a old PTO he had
> lying around, and amazingly, after several hours it was right
> on within a hz or 2.
> The question is, how would someone set one of these up for
> an old TT, say the Triton IV, so that it would work with the automatic
> CW off-set on xmit and the RX manual off-set?
>
> It would appear that the stabilizer would lock on to the new freq if
> sending CW, since both the automatic cw off-set and the manual RX
> offset are obtained by shifting the PTO frequency. Are we missing
> something? Or is it for SSB only?
>
> BTW, I know there are newer citcuits that should work even better,
> but wonder how they get around this seeming problem.
> John, K4AVX
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