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Re: Frequency Accuracy and stability

Posted by Elecraft mailing list on May 19, 2021; 10:54pm
URL: http://elecraft.85.s1.nabble.com/Frequency-Accuracy-and-stability-tp7669697p7669699.html

I count beats.  One beat in 1 second and I'm off 1 Hz.  One beat in two seconds and I'm off 1/2 Hz.  Easiest done if the side tone and received signal are adjusted to be close in amplitude and there's little/no QSB.   Zero beats, and the frequencies would be exactly the same, but the practical limitation is probably 1/4Hz in good conditions.  The only things required are a reference, like WWV, and my ear.

That is, after all, what the term zero beating means, adjust frequencies to be the same until the beats stop.

Lou W7HV



    On Wednesday, May 19, 2021, 3:30:49 PM MDT, Bob McGraw <[hidden email]> wrote:  
 
 I ordered my K3S with "KTCX03-1-F TXCO 1ppm f/w correction to 0.5ppm".  
K3S-F s/n 10163

I use CW mode and CWT mode and tune to each of the WWV frequencies.  By
pressing SPOT the radio resolves to the WWV frequency but will show any
error either + or - of the WWV frequency.   By tuning up about 25 Hz and
then pressing SPOT and then tuning down about 25 Hz and using SPOT one
can easily see the error amount.    If all is correct, it will return to
the WWV frequency +/- 0.0 difference.

I check 4 or 5 WWV frequencies and note any discrepancy.  I then can
adjust the REF CAL up or down as needed and then re-check the WWV
frequencies as described above.

I find this method is preferable to the "zero beat" method and assures
the radio on all bands is +/- 2 Hz or better.   Good enough for me.

73

Bob, K4TAX


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