[Elecraft] Calibration with CHU via Spectrogram Software

[JimWMiller@aol.com]

Don, Earl,Tom & All,

What Earl says makes sense. I may fall back on what the manual says and 
connect the freq counter and freq counter probe to TP-3 and adjust for 4.00 
MHz  I'll compare with CHU and W1AW.  I may fine tune at that point or not.

The Elecraft spec is < 100 Hz drift and I consider that good, especially when 
its better on the lower bands.  Hey, my National HRO-5TA1 (circa 1946), 
drifts about 10KHz and requires a 2 hour warm up !!! 
73 for now,
Jim, WA2UMP
K2: 2679
> ===
> 
> You are correct that directly measuring the 4.000 MHz oscillator is likely
> to pull the frequency.
> 
> The solution is to use the method outlined in the manual - connect BOTH the
> K2 internal frequency counter probe AND the external frequency counter to
> the same point (TP3), then adjust C22 so that both counters display the 
> same
> frequency.  This method will assure you that the 4.000 oscillator is set as
> close as the calibration and accuracy of your external counter will allow.
> 
> Using WWV or CHU or other standard frequency involves an interative
> process - set C22, then run CAL PLL, check for zero beat, and do it again
> and again until you have it right...  Using the external counter is much
> easier and straightforward.   I guess you could fine tune to WWV or CHU
> after doing the initial adjustment with the external counter, but if you 
> are
> within 20 Hz or so, I wouldn't bother for the K2 may drift as much as that,
> and would make attempts at further refinement just an exercize in
> frustration IMHO.
> 
> 73,
> Don Wilhelm  - Wake Forest, NC   W3FPR home page: http://www.qsl.net/w3fpr/
>   QRP-L # 485   K2  SN 0020   mailto: w3fpr@arrl.net
> 
> *** Life is what happens when you're making other plans -- Mike Cross  ***
> 
> ----- Original Message -----
> 
> > Tnx for the advice. Yes, I can use a freq counter but I'm afraid that
> > connecting a probe will pull the freq. Can also listen for the 4.000 MHz
> on a
> > receiver but then its only as accurate as that receiver.  Perhaps this is
> > good enough but people are talking about accuracy within 30 Hz or so. I'd
> > like to use the method that has the best accuracy.  Seems like 
> fine-tuning
> to
> > atomic clock accuracy at least theoretically is the way to go.
> > Has anyone had good results with the CHU method?
> 
> 
> 



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