[Elecraft] K2 dial alignment

[paul]

Hi Don,

I have read your website (and 50+ posts) and done this procedure about 5 
times over the last 3 days - each time with the same result (no change).

Followed a procedure that made the two frequencies (TP3 and TP2) 
exactly 10MHz apart by varying C22.  Ran CAL PLL (7.1 Mhz) and then ran 
CAL FIL.  Made small changes to each BFO frequency on all modes 
(USB,LSB,CW,/CW) and Xtal selections.  No change at all - WWV is still at 
10.012 MHz.  WWV voice is perfectly tuned in both USB and LSB.

Right now the radio works great except for this problem.  Guess I will try
again when I get the new firmware.

Thanks for your help,

Paul
AD5IW

On Mon, 3 Dec 2007, Don Wilhelm wrote:

> Paul,
> 
> The exact frequency of the 4 MHz (nominal) reference oscillator may be
> slightly different than exactly 4 MHz. 
> If you have a well calibrated external frequency counter, you can adjust the 4
> MHz reference (adjust C22) by measuring the frequency at TP1 with both the
> internal counter and the external counter - adjust C22 until the internal
> counter reads the same as the external counter.
> 
> Another method that provides even greater accuracy is the method outlined on
> the Elecraft website on the Builder's Resource page -
> http://www.elecraft.com/Apps/K2%20C22%20Adjust%20App%20Note.pdf.
> This method requires no extra calibrated equipment, but there is a requirement
> that the standard station be tuned with precision.  When using WWV, I use
> Spectrogram to observe the audio output tones, knowing that WWV transmits
> tones of 500 and 600 Hz on alternate minutes (there are silent minutes and one
> minute of 440 Hz tone as well).  If the tones line up with my Spectrogram
> markers at 500 and 600 Hz, I know that WWV is properly tuned within one or two
> Hz.
> 
> After setting the 4 MHz reference, run CAL PLL and CAL FIL changing each BFO
> and the resulting frequency should be within 20 Hz of the correct dial
> reading.
> 
> For more information, please refer to my website article on K2 Dial
> Calibration www.qsl.net/w3fpr
> 
> 73,
> Don W3FPR
>