While I can't guarantee it, from your description, it sounds suspiciously
like the OFDM version of BPL to me ...

Where are you geographically located?

Check out the videos at the ARRL site ... If I recall correctly, the last
test area on
the video is the OFDM system ...

Video showing results of ARRL testing in MD, VA, PA and NY
Internet: http://216.167.96.120/BPL_Trial-web.mpg - for those with broadband
access
Internet: http://216.167.96.120/BPL_Trial-small.mpg - for those with slower
access
Author: ARRL technical staff
I am cc'ing Ed Hare of ARRL on this - he may be able to shed additional
light on this and will probably want to correspond with you by e-mail.

It is VERY important that cases of BPL interference be determined
conclusively and well-documented - we can't afford to "cry wolf" at this
critical juncture.

73,

Carl - wk3c

"Pete Holden" wrote in message
news:zjTWb.290841$I06.2983429@attbi_s01...
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