[Elecraft] K2: VFO clicks/pops in the presence of strong signals

[Don Wilhelm]

Mike,

You are hearing the PLL reference transitions (Sverre explained it nicely),
but they should be at a low level and not very noticable unless you listen
closely.

If you happened to run CAL PLL without the bottom cover in place, those
clicks will be louder than normal - so re-run it with the cover on.

You may be able to reduce the intensity of the clicks/pops by moving the PLL
reference voltages a bit - be certain 80/75 meters is entirely within the
specified range.  Of course, re-run CAL PLL after shifting the PLL range.

73,
Don W3FPR

----- Original Message ----- 

>   I have just completed "Test and Alignment, Stage II" of K2 #4137.
> Everything seems to have gone very well -- all Voltages were in range and
it
> seemed that everything worked as it should. However, I've now run across a
> strange problem.
>
>   I find that clicks/pops occur when I tune the VFO in the presence of
> strong signals. For instance, if I set the XG1 for 50uV and tune the VFO
up
> and down from the XG1's frequency of 7040kHz, I hear clicks/pops (about
> S-5/6) when the VFO transitions the following boundaries:
>
> 7015.79/80 (click/pop getting very weak here)
> 7020.79/80
> 7025.79/80
> 7030.79/80
> 7035.79/80
> 7040.79/80 (XG1's signal is theoretically centered at 7040.00)
> 7045.79/80
> 7050.79/80
> 7055.79/80 (clock/pop getting very weak here)
>
>   The clicks/pops occur when I roll the VFO's last two digits
> back-and-fourth across the .79/.80 boundary. The clicks/pops do not occur
> when I turn off the XG1.
>
>   I have also noticed that I can hear these clicks/pops when I get up
around
> 7300 and strong broadcast stations are present.
>