[Elecraft] K2 Frequency Stability

[John Grebenkemper, KI6WX]

Dave;
The data I have from 6 K2's on frequency stability shows that the K2 VFO
drifts with temperature by between -0.4 and -1.1 ppm/C with an average drift
of -0.8 ppm/C.  Ten meters is clearly the worst band since this involves the
VFO tuning to 25 MHz.  At this frequency, the average drift would be -20
Hz/C.  If your VFO drifts significantly worse than this, try changing X1 and
X2 on the RF board.

To get the best absolute frequency accuracy, the 4 MHz oscillator on the
control board must be precisely adjusted.  There have been several ways
described to this on the Elecraft site and in the mail archives.  Because of
the interactions between the 4 MHz oscillator and CAL PLL and CAL FIL, a
error in the 4 MHz oscillator can translate into different errors on
different bands.  No matter what you do, I doubt whether you will be able to
get the absolute accuracy much better than 50 Hz across all bands.
-John
 KI6WX

> Hi Guys
>
> 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
> and the frequency accuracy isn't anything to get excited about at 206 Hz
low
> on 29 MHz compared to being within 1 Hz on 7 MHz (figure varies from K2 to
> K2 and from band to band and also depends on alignment).
>
> I need to be up early in the morning (Friday) but will try and check my K2
> at the weekend and post the drift figures for 29 MHz. This is checked
> against an off-air frequency standard on a commercial counter reading to
0.1
> Hz.
>
> 73's Dave, G4AON
> K2 #1892
>