[RFI] Another strange emitter

[Pete Smith]

This one showed up a few months ago.  There are often many of these 
scatttered across the bands; other times, fewer.  It is loudest on 160 and 
80 but is occasionally audible up to 20M.  Because it has no apparent 
modulation, I have not been able to track it down with my AM-only portable 
radio.

The screen-shot at www.pvrc.org/~n4zr/80m.jpg gives a visible waterfall 
picture - as you can imagine, it sounds on a CW or SSB receiver like two 
alternating tones about 100 Hz apart, each drifting slightly, cycling about 
once a second.  I can provide an audio recording if that would be helpful, 
but if anyone can hel[p me identify this as to source, it'd be great.

73, Pete N4ZR