[Elecraft] Noise in K2 on 160m

[Sverre Holm - LA3ZA]

My CQ WW contest time is over - that is I was only after the DX and as
darkness has come 20, 15 and 10 meter have more or less closed.

Much to my surprise I was also able to work some stations on 160m
tonight. The antenna is a 75 m horizontal loop with a 4:1 W1CG balun,
and I know this is not supposed to be very good for 160 m, but anyway I
worked OZ, GM and G. This is the first time ever that I have worked 160
m. 

I notice that the band is very noisy, but my K2 behaves in a strange way
as I have to work it with the Attenuator on and RF gain in the 10 or 11
o'clock position to get rid of a kind of noise that makes it almost
impossible to copy anything. The Noise Blanker makes it a little bit
easier, otherwise the RF gain has to be turned down even more. The noise
seems to come as the RF gain crosses a threshold and then it will
distort the received CW also. To me it seems like some sort of overload
or oscillation in the RF/IF part of the receiver. I have also noticed
this kind of behavior on 80 m from time to time.

Any clues about what this can be?

Sverre Holm, LA3ZA
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