[600MRG] Strange decodes

[Rudy Severns]

This is clearly a spurious decode but it sure looks real.  It's interesting 
how wspr can generate these!

      2014-09-14 15:30   IW1BGB   0.475753   -33   4   GK64   50   WD2XSH/20 
CN83   7784   311


I get spurious decodes all the time but usually they're very obvious.  This 
one I had to look at the map.  GK64 is in the middle of the Atlantic!

New subject.  For many months I've been seeing a trio of signals from 
475.775 to 475.930 kHz.  I see them while looking at WSPR signals with ARGO. 
The signals are clearly two tone FSK but the shift is only about 3 Hz with 
tone periods of a few seconds.  They run for long periods but they do shut 
down and resume occasionally.  This is somebody doing something??  Any ideas 
anyone?   They're not QRM at the moment but it would be nice to figure out 
the source.

73, Rudy