"4nradio" wrote in message
news:Bbt3d.227104$mD.150628@attbi_s02...
What you're hearing is almost certainly CODAR transmissions. They are a
radio-based method of tracking shifting dunes and eroding coastlines at
sal****er beaches. The technology is used on both coasts of the USA. In
the
DX hobby press, you'll see these signals referred to as "the swisher" or
"space zapper". They usually are centered on 4800, but are audible some
ten's of kilohertz either side.

I hear CODAR fairly strong at home, but on coastal DXpeditions the racket
is
really annoying in the lower half of 60 meters.

Guy Atkins
Puyallup, WA USA

Thanks for that. I think I'm going to start recording these, and putting
them online. No one else seems to be doing it. Might make for a mildly
interesting site for radio folks.