In article .com,
tom k in L.A. wrote:
what is all this "PSHHHHHT" [pause] "PSHHHHT" [pause] "PSHHHT"
[pause] I hear on some shortwave freqs?

Er, a frequency would be nice.

I assume you're in AM mode. To really get a handle on it, listen
in SSB mode.

A couple of possibles, one is a ARQ-TOR signal. This is a ship to
shore digital system for teletypes (ARQ - automatic request (for
retransmission?) TOR - Telex Over Radio). With SSB on, it's
a Dreep-Dreep-Dreep signal. Around 6300 kHz, I think, but there
are almost a dozen maritime mobile bands where it can occur.
Hams also use it, in a slightly different way. Maritime users
have two frequncies, one for the ship, one for the shore station.
Hams use the same frequency for the shorter ack packet, so it's
more like Dreep-drp-Dreep-drp with one side or the other having
a stronger signal.

Another is the dreaded CODAR. This is some sort of over the
horizon radar used to measure wave heights or something like that.
Depending on where you are in the signal, it sounds like a couple
of chirps or a chirp-swish-chirp-swish. 12095 kHz is one hangout,
around 4800 kHz is another.

Mark Zenier
Googleproofaddress(account:mzenier provider:eskimo domain:com)