[Elecraft] A minor C22 question

[W3FPR - Don Wilhelm]

Mike,

I don't have any measurement data to support it, but I do believe that the 
oscillators (BFO, PLL, VCO) can be influenced by temperature and the 
proximity of objects to the frequency determining components - the 
difference should be slight, but could account for 10 to 30 Hz in the end.

Also, remember that CAL FIL must be run to for the results to be correct. 
Even if the filters are already correct, each BFO must be moved a notch and 
then moved back for the new values to be written.  Failure to do that will 
look like your calibration efforts 'just didn't work right'.

You are correct in saying that once the values are written into EEPROM, the 
reference oscillator is out of the picture - but those values only represent 
voltages which SHOULD produce a specific frequency - if the conditions 
around the frequency determining components of the oscillator are not the 
same as when the values were written, the resulting frequency may be a bit 
different.

Now, I must admit that the differences are slight - but for those who would 
struggle to get things 'right on', you should realize that these factors 
will influence your results.

73,
Don W3FPR

----- Original Message ----- 
>
> Not really an issue.  Get C22 right with the cover off and right away do
> the "cal pll" before putting the cover on.  After that it doesn't matter
> what happens when the cover is replaced 'cos it has no effect whatsoever
> on calibration.
>
> Regards,
>