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
_______________________________________________
Elecraft mailing list
Post to: Elecraft@mailman.qth.net
You must be a subscriber to post to the list.
Subscriber Info (Addr. Change, sub, unsub etc.):
http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/subscribers.htm
Elecraft web page: http://www.elecraft.com
