[Elecraft] Sync AM and checking VFO accuracy using WWV

[Don Wilhelm]

Brian,

The higher the WWV frequency, the possible percentage of error goes 
down.  One or two Hz is a smaller fraction of 20MHz than at 5MHz.

In the K3, you are calibrating the reference (out of the synthesizer) 
rather than calibrating the actual VFO frequency.  The actual VFO 
frequency is derived from and phase locked to that reference.

73,
Don W3FPR

On 12/18/2016 12:17 AM, Brian Denley wrote:
> Fred, Don:
> I ask because I am curious.  On any older receiver, calibration at 20 MHz would not guarantee cal below that ( or at any other frequency ).  One could be 5 hz high at 30 MHz but 10 hz low at 7 MHz.  Why is the K3 different?
>
> Brian Denley
> KB1VBF
> Sent from my iPad
>
>> On Dec 17, 2016, at 3:43 PM, Fred Jensen <k6dgw at foothill.net> wrote:
>>
>> I guess it depends on how accurate you want your K3 frequency display to be.  I think AM-S will warp the frequency a tiny bit to sync the carrier so that may not be the best mode.  I'd also go as high as you can on WWV.
>>
>> Wayne suggested a method that is somewhere on the E-site which I used--
>>
>> Use the highest WWV frequency that you can hear well.  USB or LSB, WIDTH to 500-800 Hz, SHIFT so can hear the carrier beat note [it will be very low].  CONFIG-->REF CAL, wait for a tone-less minute and adjust REF CAL for exact zero beat.  You'll be counting the pulsations in the background noise as you come up on zero beat.
>>
>> I got mine to about 10 seconds per pulsation on 20 MHz back when there were sunspots.  That's an accuracy of 0.1 Hz and everything below 20 MHz will be at least that good.
>>
>> 73,
>>
>> Fred K6DGW
>> - Sparks NV DM09dn
>>
>> - Northern California Contest Club
>> - CU in the Cal QSO Party 7-8 Oct 2017
>> - www.cqp.org
>>
>>> On 12/16/2016 5:12 PM, Michael via Elecraft wrote:
>>> If I set my K3's VFO to WWV at 5.000000 MHz with AM-S on....and I adjust
>>> "REF CAL" to a number where
>>> my VFO's frequency readout is exact or near this number +/- maybe a Hertz
>>> or two. Is this an accurate way to calibrate my K3?
>>>
>>> It seems to be very accurate as far as I can tell.
>>>
>>> Has anyone used this method?
>>>
>>> Michael
>>> N2ZDB
>>
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