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Topband: K3 NOISE ONLY ON 160m

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Subject: Topband: K3 NOISE ONLY ON 160m
From: "Bill and Liz" <magoo@isp.ca>
Date: Fri, 11 Nov 2016 12:58:48 -0500
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My K3 developed an S2-3 noise level only on 160M. I was able to prove that this 
noise was being internally generated by the radio and was not external.  At 
first, thought that it was being generated when the KSYN3 board for the 
sub-receiver began to unlock...every time the PLL voltage ran out of lock range 
the noise would start...or so it seemed.  After servicing the offending KSYN3 
board and solving the unlocking problem I also believed that I had  solved the 
mysterious S2-3 noise on 160M.

Unfortunately, even with the sub-receiver KSYN3 board now operating correctly, 
the noise intermittently returned, usually when I was attempting to hear a very 
weak DX station.  Often the noise would begin very slowly after the radio had 
been on for a few minutes, build and remain.  Sometimes switching off the K3 
and leaving power off for several minutes restored proper 
operation....sometimes not.

Anyhow, I accidentally discovered (while working on something else under the 
hood) that pushing on the aluminum plate to which the two KSYN3 boards are 
attached would make the noise disappear and then come back, depending on which 
way I applied pressure.  I had found the problem!

I removed the board for the main receiver and cleaned all the contacts 
(Elecraft suggests changing out the pins for gold plated types which they will 
supply).  I tightened the bolt holding the board to its mounting plate-it was 
somewhat loose.  I re-installed the board and tightened down both machine 
screws after dabbing some NuTrol on the attachment points.

Problem gone!  Now when I ground the main antenna connector the receiver is 
completely quiet as it should be...no noise, no hint of noise...nada.

Bill VE3NH
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