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 > > _______________________________________________ Elecraft mailing list Post to: [email protected] You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com
