[Elecraft] K2 VFO Calibration

[Don Wilhelm]

Tom,

Rather than relying on the XG3 to set your K2 VFO, turn to my website 
www.w3fpr.com article on K2 Dial Calibration for the procedure I use.  I 
highly recommend using Spectrogram (or other audio spectrum analyzer) 
not only for aligning the filter passbands but also to determine when 
you have tuned accurately to the WWV frequency (use 15 MHz if you are 
able, the error is smaller than using 10 MHz.

Note that there is a receive offset equal to your sidetone pitch used 
for CW mode which makes it very difficult to use a CW signal source when 
setting C22 - much better to use an AM station of known frequency such 
as WWV.

If you need Spectrogram, look for the link at the bottom of my home page 
- the files are known to be clean - I have heard of some on the web that 
contain nasty stuff.

The VFO will be quite linear if you follow the instructions in the 
article --  First set C22 correctly, then run CAL PLL, then run CAL FIL 
and 'change' each BFO to make the K2 read the BFO frequency into EEPROM 
based on the current setting of C22.
Once both those processes have been run, there is no longer a dependency 
on the 4 MHz oscillator accuracy, the frequency display is based solely 
on the data in the EEPROM.

73,
Don W3FPR

On 6/1/2013 2:13 PM, Tom Field wrote:
> I have completed the K2 and am in the process of VFO calibration
>
> I have a XG2 signal generator that I calibrated with a lab frequency
> counter.
> Here are my  results
>
> Radio                                         XG2
> Difference  (K2-source)
> 1460.00
> 14060.395                               -0.395
> 7041.16
> 7040.55                                   0.715
> 3579.30
> 3579.223                                 0.077
>                                                   WWV
> 10000.29
> 10000.00                                 0.29
>
> To me this points out some non-linearity in the VFO.
> The question is whether I should correct the VFO and by how much.
>
>