[Elecraft] K3 Receive De-sense Problem

[Hank Garretson]

For the past few months, I have had intermittent receive de-sense with my
K3/100-F, Serial 1523. Firmware 5.14, 2.13, 1.19 installed this week, but
de-sense was there with previous firmware.

Intermittently receive sensitivity will drop about ten dB. Usually happens
after transmitting, but sometimes happens spontaneously with no
transmitting. A dit usually restores sensitivity. If I don't dit,
sensitivity randomly restores itself.

CW, SSB, RTTY. All contest bands. (Don't do WARC.)

I have one-by-one eliminated my BCD antenna-switches, my ACOM amplifier,
and my antenna/dummy load switch. With these items in or out of line, I
still get intermittent de-sense.

Which leads me to believe the problem is with the K3 itself. (It could be
one of my coax patch cables, but I suspect not.)

KXV3 installed, but use ANT1.

SUB installed. Intermittent de-sense with and without SUB engaged.

Suggestions?

73,

Hank, W6SX