[Elecraft] 10M birdie and other assundries

[Vic K2VCO]

J F wrote:
> Just out of curiousity, after spending some time on
> 10M during ARRL 10, I noticed a birdie around
> 28.019/20. Is there a way to eliminate this or move it
> below 28.000?

Yes, but even I haven't had the guts to implement it.

Replace the diode t/r switch with a reed relay such as the Matsushita 
RSD12V.    Reduce the power level of the bias oscillator and remove the 
high voltage multiplier section so you can get -12v for the RS232 
interface with less stray RF floating around.  Alternatively, find a way 
to power it from the computer (and some RS232 ports will apparently work 
without the -12v at all), so the bias oscillator can be completely disabled.

I tried various forms of shielding, filtering and bypassing without 
success.  A friend pointed out to me that the birdie is a result of 
mixing between VHF harmonics of this and another oscillator in the K2, 
so that explains why it's so hard to kill.
-- 
73,
Vic, K2VCO
Fresno CA
http://www.qsl.net/k2vco