[Elecraft] SW broadcast to calibrate against.

[Ian White GM3SEK]

Ron D'Eau Claire wrote:
>Ian wrote:
>
>The higher the reference frequency, the more accurately you can set the
>TCXO
>
>-------------------
>
>Is that correct? I don't know the details of Wayne's firmware, but the
>accuracy of a synthesized rig is normally independent of the frequency being
>received.
>
The error in ppm is independent of the frequency, but the resulting 
error in Hz is proportional to the frequency.

>I go for the highest frequency standard available when I'm trying to zero
>beat some lower-frequency oscillator as accurately as possible (such as when
>I set my 4.000MHz counter reference oscillator zero beat to WWV at 20 MHz),
>but that I don't believe that's what we're doing here.

On the contrary, that is exactly what you are doing with the K3 as well.

The firmware initially assumes that the TCXO frequency is 49,380,000Hz. 
The REF CAL adjustment is telling the firmware what the true frequency 
of the TXCO is, and then the firmware will re-calculate all the 
transmitted, received and displayed frequencies in proportion to that 
new value.

To set REF CAL with the minimum possible error in ppm, the zero-beating 
should therefore be done at the highest possible signal frequency.

>I have set my K3 on a BCB band station at 830 kHz to within 1 Hz and noted
>that WWV at 15.000 MHz is still within 1 Hz.

That is because you did a really good job at 830kHz :-)



-- 

73 from Ian GM3SEK