On my Icom 756 spectrum scope I'm getting S9 peaks every 2kHz or so all
across the HF spectrum from 3mHz to 30mHz. This doesn't look at all like
QRN since it's regular and discrete and they're narrow signal peaks,
narrower even than a ham cw signal, all peaks the same strength. When I
switch to a vacant antenna position, or to my dummy load, there is nothing,
so I'm assuming it isn't coming over the AC line. The noise signal is
stronger on my vertical antenna than on my horizontal loop.

I've seen this before, intermittently -- one minute on, two min off, 20
seconds on, etc. But, today it's been going on for at least a couple of
hours.

Ideas anyone?

Thanks, Pete