"Larry Dighera" wrote in message
news
On Wed, 14 Mar 2007 20:29:09 -0700, "Ron Baker, Pluralitas!"
wrote in
:


"Larry Dighera" wrote in message
. ..

Tx Location: Unknown
Station: Unknown
Program:
S4 noise level with two-second S8 transmissions, followed by one
second of no carrier. Modulation method unknown, but there seems
to be a marginally audible low frequency beat in the carrier.
Occasionally the pattern is punctuated with very short pulses of
other pulse-type modulation. Probably some sort of telemetry?
Language: None
Time: 0134U
Frequency: 6,360.0 kHZ
Mode: USB (seems to work best?)
Signal: S8
Readability: ?
SINPO: 35444

Rx Location: Southern California west coast, USA
Equipment: Drake R8B
Antenna: Datong Model IB5 active rotatable dipole
Azimuth: ~160* - ~340* True

It's a maritime ute. Modulation is SITOR.


Ah. Many thanks. I was completely unfamiliar with SITOR. There is a
simple explanation of that mode he

http://en.wikipedia.org/wiki/SITOR
SITOR is used commonly on shortwave bands, where it is used to
transmit maritime-related information such as weather forecasts
and storm warnings. In the United States, it is regularly used by
the United States Coast Guard.

There is also a link to an audio file, so the modulation mode can be
identified.

SITOR has an aurally easy to identify idling pattern.
Synchronization bursts are transmitted every second or so and last
for slightly more than one second. Every few sync bursts, a Morse
identifier of three letters is transmitted (for example NMO in
Honolulu).

However, the wiki audio sample, while similar to that heard on 6360
kHz, seems different. Perhaps that is due to my choice of detector,
but I don't recall hearing any Morse code.

I'll upload both the wiki SITOR audio sample file and the sample of
what I received to alt.binaries.sounds.radio.misc, so you can judge
for yourself.

I went there but it was full of other things.
I didn't see anything from you.


Globe Wireless, KEJ, Hawaii?
Globe Wireless, KPH, San Francisco?

There is information for those types of stations he

NATIONAL WEATHER SERVICE MARINE PRODUCTS VIA U.S. COAST GUARD HF
SITOR: http://www.weather.gov/om/marine/hfsitor.htm

However, the sound of the sample signal offered he

Click here to listen to what a typical SITOR signal sounds like on
the air: http://www.weather.gov/om/marine/hfsitor.wav

seems to differ from that heard on 6360.0 kHz.

Compare the files I posted in alt.binaries.sounds.radio.misc, and see
what you think.


I have about 70 sitor stations programmed into my
radio controller. They operate 24/7. You can hear
them whenever propagation is open to their location.
There are typically 20 or so audible at any time.
One that blew me away though is TAH Turkey
on 12.654. (I'm in socal too.) It has come in loud and
clear several times. But typically I hear Coast Guard
NMO, NMN, WLO from Hawaii, Point Reyes,
New Orleans. It is not uncommon to hear Chinese
stations too, XSG, XSQ. Have heard UDK-2 Russia
also.

There are public and private maritime sitor utes.
The public stations send their call letters in CW.
The private ones don't.

There are two modes, SITOR-A and SITOR-B.
They kind of blur in my mind.
Generally it sounds like they send an idler/beacon/
hailing pattern in FSK. Then occasionally break
into an ARQ (Q)PSK packet data mode. That often sounds
like a beep and a burst of 'noise'. The beep allows
the receiver (ship) to sync to the exact frequency. The
'noise' is PSK or QPSK data. In the pauses between
bursts the transmitter listens for an acknowledge
from the receiver. We eavesdroppers hear
the data packet from the base station but typically
can't hear the acknowledge from the mobile (ship).
(And maybe one of the modes is an FSK ARQ
mode too.)

The private utes are certainly encrypted. They
are selling email and weather news service.

Happy listening,
rb