On Tue, 2009-04-21 at 09:08 -0700, lee berman wrote:
> I am attempting to correct the thermal drift on my 580 Delta PTO, by using a
> Direct Digitally Synthesized VFO as a remote VFO. The DDS output is said to
> be ~500mV P-P (I've not measured it myself). To date, I had no success. I
> wonder if anyone else on this reflector has successfully done this and can
> point me in the right direction. The unit I'm trying is the one by N3ZI.
> Other "fixes", such as PTO rebuild, and the K4DPK unit have worked well for
> many other hams, but not me. The drift is definitely in the PTO, defintely
> thermally induced and does not settle out after hours of on time, so this is
> my latest effort at ending it.
> thanks, ~Lee, W1IDZ
Have you checked to see that all the temperature compensation capacitors
are soldered to the PC board? I found that to be a problem in a Kenwood
that drifted too much.
Looking at the PTO schematic for my Corsair II, I suspect the VFO
voltage is a lot more than half a volt peak to peak.
73, Jerry, K0CQ
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