[Elecraft] K3(s) main oscillator calibration

[Bob McGraw K4TAX]

In referencing TF.NIST.GOV on page 251, I find it stated;

"When high accuracy is not required, probably and fastest way of 
comparing the frequency of an oscillator to a broadcast standard is the 
familiar heterodyne or zero beat method. "

And then on page 253, I find it stated;

" Usually, however, it is difficult to adjust an oscillator to exactly 
zero beat with an HF carrier beyond the ground wave range of the 
transmitter.  The problem arises from rapid fluctuations in the received 
signal strength and from propagation flutter in the received frequency."

References are: THE USES AND LIMITATION OF HF STANDARD BROADCAST FOR 
TIME AND FREQUENCY COMPARISON.  John T. Stanley, NIST.

As I indicated earlier, a frequency accuracy of +/- 1 Hz for ham radio 
purposes is adequate.  Likewise for time accuracy +/- 0.1 second is 
adequate.

73

Bob, K4TAX


On 6/10/2020 11:52 AM, w4sc wrote:
> How much doppler shift should be expected?
>
> Sent from Mail for Windows 10
>
> From: W2xj
> Sent: Saturday, June 6, 2020 5:31 PM
> To: w4sc
> Cc: wes_n7ws at triconet.org; elecraft at mailman.qth.net
> Subject: Re: [Elecraft] K3(s) main oscillator calibration
>
> the problem with WWV is doppler shift.
>
> Sent from my iPad
>
>> On Jun 6, 2020, at 5:27 PM, w4sc <w4sc at windstream.net> wrote:
>>
>> I like the zero beat WWV method.  Used it in the Navy to calibrate / PM the 10MHz frequency standards aboard ship. Requires the least amount of test equipment!  If you can receive WWV on 20MHz to calibrate the K3/K3S, all the better,
>>
>> Using a frequency counter I would think  0.1Hz resolution and attending accuracy would be in order, plus an accurate time base in the counter, GPS locked,,, or oven-ized, on all the time reference ,,, ect.
>>
>> Ben W4SC
>>
>>
>> Sent from Mail for Windows 10
>>
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