[Elecraft] K2 frequency drift

[Kevin Schmidt]

Don,

I agree about warm up drift.  Perhaps I misunderstood Adam, but I
thought that his problem was that even during normal usage he found
objectionable drift when he operated his KPA100 for a while. I presume,
perhaps wrongly, that this is most likely coming from the PLL since I
thought that the heating due to the KPA100 was what lead John, KI6WX to
come up with the thermistor compensation.

73 Kevin w9cf

On Sun, Dec 24, 2006 at 03:26:08PM -0500, Don Wilhelm wrote:
> Kevin,
> 
> The RA resistor on the thermistor board is intended to compensate for drift
> AFTER warmup - such as drift that might occur due to the additional heating
> when the KPA100 is transmitting.  I do not believe it would be fruitful to
> attempt to compensate for the initial warmup drift that one may find in the
> K2 - and you may wind up overcompensating and find the drift after a warmup
> period would be greater - it would not be good to have a K2 that does not
> drift when first turned on and then begins to drift after some warmup
> period.
> 
> Or perhaps better said, the thermistor board provides compensation for the
> PLL reference oscillator.  There are many more components involved in the
> initial warmup drift - the BFO is one.
> 
> It would be interesting to try, but would take a lot of controlled test
> conditions to verify the results.
> 
> 73,
> Don W3FPR
> 
> > -----Original Message-----
> >
> > The K2 PLL Ref Upgrade manual gives some information on typical drift i.e.
> > 5 to 20 Hz per 15 degrees F on 20 meters. It also explains how changing RA
> > on the thermistor board can better compensate for the drift.  Since your
> > drift is consistent, I think you should be able to reduce it by adjusting
> > RA on the thermistor board.
> >
> > 73 Kevin w9cf
> >