[TenTec] PTO stability

[David McClafferty]

I found that the drift in my Omni C was due to
temperature changes on the varicap diodes used for
RIT/XIT and band offset. They are in the circuit all
the time even if the RIT/XIT is off. With these diodes
disconnected the PTO was rock solid. I never did
around to try compensating for this as I got a good
deal on an Omni V and sold the C.

73, Dave, VE1ADH

--- Clark Savage Turner <csturner@slonet.org> wrote:
> An old topic, I remember this being discussed, but
> can't find my old 
> notes.  Anyone have a few hints or suggestions to
> slowing down the drift 
> in my Ten Tec PTO?  I have rebuilt it, the drift is
> over 1 KHz in an 
> hour and it continues, but slows down, for many
> hours.  I suspect I need 
> to change the temp compensating cap in there and I
> have a friend with 
> many boxes of temp compensating caps I can use to
> try.
> 
> Has anyone chosen caps for their PTO and has any
> simple, basic advice 
> that would help me?  I am not trying for perfection,
> I just need a few 
> hints to get down to 20 or 40 Hz drift after a
> little warmup, like my 
> other PTO.
> 
> Any tip at all appreciated.  I have a freq counter
> and plan to tack 
> solder in the replacement caps, then take some data
> and see where I get 
> after a few tries.  Make sense?
> 
> Clark
> WA3JPG
> 
> _______________________________________________
> TenTec mailing list
> TenTec@contesting.com
> http://lists.contesting.com/mailman/listinfo/tentec


______________________________________________________________________ 
Post your ad for free now! http://personals.yahoo.ca