Re: [TenTec] DDS VFO as remote VFO?

[Bwana Bob <wb2vuf@gti.net>]

Lee:

The easiest way to fix thermal drift is to change the temperature 
compensating capacitor in the PTO. This is the cap that is shown as 
"value selected in production" on the PTO schematic. You will need to 
try different values of capacitor and they must be of the N750 (negative 
750 ppm) type. Unfortunately, N750 caps are hard to find.  Maybe Ten Tec 
has some spares.
                                73,

                                Bob WB2VUF

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
>
>
>
>
>       
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