[Elecraft] Re: Simple K2 RX mod handles extremely strong on-frequency signals

[Dave Sergeant]

One other place where this strong signal overload situation occurs 
here in 
my own shack. As I have mentioned before, I use a homebrew 5W VXO 
transmitter for our 60m band. I am using the K2 as the receiver in 
conjunction with a Datong UC1 upconverter with the K2 on 28MHz. 
Perhaps 
because I have taken the lazy way out, and in any case because I need 
to 
monitor my own transmission for netting and sidetone purposes, I have 
not 
implemented any muting of the receiver in transmit other than 
switching the 
antenna over. Hence my s meter goes hard against the end scale (if 
leds can 
do that!) when I transmit and I get the overload audio effect Wayne 
mentions. Cure is easy, I either offtune the receiver 100Hz or so or 
I 
switch out the K2 preamp, in any case it is only when I tune spot on 
my 
transmit frequency that I hear the howl.

I imagine putting in Wayne's diodes would cure the problem, but that 
means 
taking the lid off the K2 which is doing an excellent job working 
stations 
at the moment! I could equally do the job properly and mute the 
receiver 
quite a few db in transmit.

So the problem is not such an unusual circumstance as some would lead 
us to 
believe.

73s Dave G3YMC

dsergeant@iee.org
dsergeant@btinternet.com
http://www.dsergeant.btinternet.co.uk