[Elecraft] K3EXREF for eme and mw

[Bruce Beford]

At first glance, frequency corrections being suspended during transmission
may have a large effect on the usefulness of the upcoming PLL board for the
K144XV. If the frequency is not compensated during TX, when maximum heating
(and therefore freq shift) takes place, it would seem that the K144XV could
still be subject to substantial drift. This would be most true during high
TX time modes like JT65 and WSPR, etc.

I would hope the need for frequency compensation during TX will be
considered and addressed, as the K144XV PLL solution is developed.

Bruce, N1RX

> Ed, KL7UW wrote:

> It hadn't occurred to me that frequency correction would be suspended 
> in Tx.  That is both good and bad, as I see it.  Good that no phase 
> jumps occur, but bad that transmitter drift is not being corrected.

> For eme digital modes this means the freq. is solely held by the TCXO 
> over the minute-long transmit sequence.  That probably will not 
> affect the K3 when running transverters as there will be no large 
> thermal change in the radio operating at mw levels.  It may see more 
> effect when I run HF/6m at 12w on my K3/10, but that probably is much 
> less than those that run the K3/100.

> I guess I will have to reserve judgement on how well K3EXREF will 
> assist operating at microwaves (mw).  As I see it now, the K3EXREF 
> will track out mid-term frequency drift of the TCXO during receive 
> sequences, so the Tx drift (if any) is limited to that which occurs 
> in 1-minute.