[Elecraft] K2 Frequency Stability

[Ron D' Eau Claire]

> I note that measurements are being conducted on 10 MHz against WWV, the
> worst band on my K2 is 28 MHz. The drift is of the order of 100 or more Hz
> 73's Dave, G4AON

First, I stand corrected. As a couple of sharp readers including Lou, W7DZN,
pointed out, the amount of drift in the PLL output is increased when it is
running at a frequency above the reference oscillator frequency. In the K2,
that means that worst case drift will be observed on 10 meters as Dave noted
above.

I ran a measurement on my K2 at 29 MHz today. From a "cold start" (the K2
had been powered Off for 12 hours) the frequency drifted downward at total
of 40 over the first 90 minutes. After that it has slowly wandered over a
range of 10 to 12 Hz of the median frequency (total drift of 20 to 25 Hz).
It seems to cycle over a period of a couple of hours although the movement
is somewhat erratic. Over a period of 5 hours the most rapid movement was 20
Hz over a period of 70 minutes. Other than that one 20 Hz shift, the rate of
change is closer to 10 Hz per hour.

With an outside air temperature of 40 degrees F, the forced air heating is
cycling on and off, shifting the room temperature probably 5 degrees each
time the furnace runs. That is probably the greatest cause of the on-going
frequency changes after the initial warm-up.

Ron AC7AC
K2 # 1289