On Aug 16, 2:09*am, dxAce wrote:

At least part of what you are hearing is most likely CODAR.

Thanks! A Google search on that term brings up http://www.codar.com/.
It's apparently a type of HF RADAR used in tracking ocean currents.
More Google hits mention the bandwidth of 30 KHz.

Interestingly, I almost wrote in my original article that its wide
bandwidth and pulsed mode of operation was reminded me somewhat of the
old Russian Woodpecker OTH RADAR (remember that nusiance?). So it's no
surprise to learn it is a radar of some sort.

Mystery solved.

--
David Barts
Portland, OR