[Elecraft] K3: interference on 50.313

[Edward R Cole]

Had a strange signal on 50.313 a couple days ago.  To memory it was 
centered on 1500 Hz and about 1000-Hz wide.  I went about looking for 
sources and disconnecting cables.  With all antenna connections 
disconnected it was still there (oh bad).  But I also wondered if a 
setting might have changed to produce it.  Recently a question about 
setting up FT8 on the K3 had me going thru my settings so I rechecked 
them.  Strangely clicking XFIL button cleared the display of the 
interfering signal.

Hmm I said to myself, noting that button also controls DUAL 
PB.  Could activating dual-PB in DATA-A mode produce this 
"effect"?  Attempting to reproduce it with the XFIL/DUAL PB button 
was unsuccessful (which is OK).  So this remains a mystery signal 
(apparently internal to the K3)?

Experts any guesses on what it was?

73, Ed - KL7UW
   http://www.kl7uw.com
Dubus-NA Business mail:
   dubususa at gmail.com