In article ,
Greg wrote:

From: "Ralph Mowery"
Organization: EarthLink Inc. -- http://www.EarthLink.net
Newsgroups: rec.radio.shortwave,rec.radio.amateur.digital.misc ,rec.ham-radio
Date: Sat, 12 Feb 2005 13:08:16 GMT
Subject: Rtty Protocol

Most hams are received in the LSB mode. Comercial statisons usually are
received in the USB mode or the reversed mark/space relationship. Also the
speed (baud rate) and shift are usually differant than the normal ham 45
baud (60 wpm) and 170 Hz shift.



"B.R. Smith" wrote in message
...
I am using Ham Scope and Mmtty to decode RTTY with my sound card. It
works fine for hame radio operators but I have found RTTY on non-ham
frquencies and all I get is garbage. For example, there is an RTTY
signal at approximately 2.042 MHZ at 1100 UTC on the West Coast and
all that displays is random characters. I suspect it has something to
do with the protocol or baud rate settings. Anyone know what they
might be? Not sure if this is maritime station or not. Thanks.


Okay, I have some questions about RTTY:

1. What unencrypted RTTY traffic is out there besides hams?

For 5 bit asynch (start and stop bits using Murray code), not much.
There may still be some very cryptic weather reports, and maybe the
North Korean news service is still at it.

Ex-Soviet maritime traffic uses a code where the Cyrillic charaters are
mapped to their close Latin alphabet phonetic matches so you can sort
of read it.

TOR, (which is actually two different ways of packaging 5 bit RTTY with
some error correction), will have some maritime traffic. There are
probably FEC-TOR weather reports from the various coast guards around
the world on shortwave , and a system that runs down on 512? kHz for
maritime information. FEC-TOR is a 100 baud narrow shift continuous
transmission. ARQ-TOR is the dREEP-dREEP-dREEP of three character blocks
or the 1? character reply from the other station. Hams use half duplex
ARQ-TOR where the same frequency is used for both stations, maritime
channels are full duplex.

2. What sort of encoder would I need to read RTTY with my NRD-525 and what
do I need to know to get it functioning?

A lot of the 1980's vintage packet controllers had numerous monitoring modes.
I built the Heathkit version of AEA's PK-232 and it will copy RTTY, TOR,
AX.25, even weather fax if you have a graphics printer of that vintage.

3. My receiver has an RTTY mode. What exactly does that do in my receiver?
Couldn't I just use USB or LSB?

Maritime RTTY channels are on .5 kHz spacing, a bit too narrow for a 2 kHz
wide USB filter if the band is busy.

Mark Zenier Washington State resident