[Elecraft] KPA freq drift

[Ron D'Eau Claire]

The Scout was a wholly different design as well. They used a
free-running VFO that was held on frequency by a very rudimentary
phase-locked loop. But when they decided to incorporate a built-in CW
keyer, they used the same logic gates for the keyer that were also used
for the PLL circuit. So whenever one operated CW with a Scout, the VFO
was allowed to 'free run'. And it was a very cheap and very drifty VFO
(an inexpensive permeability-tuned oscillator), so it would wander all
over the band in short order. I operated a Scout that would at times
drift 100 Hz in the time it took me to send my call at 20 wpm.

The Scout was nice and stable in SSB operation since the PLL circuit was
active at all times. The last time I spoke with Ten Tec about a Scout I
was evaluating for a friend, they said that they only recommended it be
used for "casual" CW in which frequency stability was not important. 

The K2 also uses 'free running' oscillators, although of much higher
quality than that PTO in the Scout, I'll wager. Still, as several ops
have noticed they will drift when subjected to temperature variations.
Even with my K2 sitting on the operating desk in a fairly stable
temperature environment indoors, I have to let it "warm up" 15 minutes
for the BFO to settle down. Otherwise, signals on the narrow (200 Hz)
filter position land outside of the passband. 

Ron AC7AC
K2 # 1289


I'm wondering if there might not be a firmware solution to the problem?
I know that Tentec tried (and failed, in my opinion) to implement this
sort of thing in the Scout.

Vic K2VCO