Topband: K3 NOISE ONLY ON 160m

[Bill and Liz]

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