[Elecraft] K3S Receiver Spurious

[Michael Tope]

Hi All,

I noticed when operating the ARRL 160 contest this weekend that my K3S 
has developed a nasty case of what appears to be some sort of LO 
spurious. When tuning across strong signals, I can now hear a low-level 
buzz (like phase noise reciprocal mixing) as I tune off them followed by 
a distinct tone peak 400 Hz off the fundamental frequency (as if there 
is a discrete spurious at that offset from the carrier frequency). I had 
noticed that a few days or weeks ago on one signal and dismissed it as 
being someone with a dirty transmit signal. After tuning across a number 
of strong signals on 160 and seeing the same phenomenon, it is clear 
that the problem is coming from my rig.

I don't know if the problem is showing up on my transmit signal as I 
haven't received any reports that I have a dirty transmit signal. I just 
listened to my carrier on a WebSDR and it sounds clean and I don't see 
any sidebands on the waterfall, so I think it may be confined to receive 
only.

So far I have been troubleshooting this remotely over the internet, so I 
haven't had a chance to twist knobs or look at the hidden menus 
carefully. Any ideas as to what might be causing this? Is there some 
problem common to the K3S that manifests itself like this?

Thanks & 73,

Mike W4EF...................