Robert Bruce Carleton wrote:

Too bad. It looks like SITOR B and NAVTEX would make a good news
clippings distribution method.

I think it is too hard to encrypt, and it is less reliable than satellite.

The decoders operate on the demodulated tones. For RTTY there are two
tones for 1 and 0. You need the radio to generate these tones by
operating in SSB mode (usually USB).

thanks. Now I know to get a working shortwave radio with SSB capability before
getting a RTTY decoder.

In article . net,
John McHarry wrote:
Robert Bruce Carleton wrote:

Too bad. It looks like SITOR B and NAVTEX would make a good news
clippings distribution method.

I think it is too hard to encrypt, and it is less reliable than satellite.

FEC-TOR is pretty trivial to encode, it's just the 5 bit teletype code,
with the start and stop bits stripped and some parity bits added, and
the three character block sent twice with some bits inverted.

Remember, this stuff was designed in the late '60s-early '70s to retrofit
onto existing RTTY gear, before the days of microcomputers. Back when
the hardware for a one byte register would cost $20 or so.

But it's all uppercase, so I doubt that any newswire would be interested
anymore.

Mark Zenier Washington State resident

In article ,
Stereophile22 wrote:
The decoders operate on the demodulated tones. For RTTY there are two
tones for 1 and 0. You need the radio to generate these tones by
operating in SSB mode (usually USB).

thanks. Now I know to get a working shortwave radio with SSB capability before
getting a RTTY decoder.

Just be aware that, if you want to get serious, you will have to get
a fairly high performance receiver, (on the par with an Icom R-75 or
the like). The maritime TOR stuff is narrowband shift (170? Hz) and the
channels are closely spaced (1/2 kHz).

I use(d) an Kenwood R-1000, which is designed mostly for audio broadcast,
and found that the 2.1 kHz narrow bandwidth (SSB) filter was often a bit
too wide and that the tuning drifted just a bit too much (maybe 50 Hz) so
that you had to babysit it to get solid copy.

Mark Zenier Washington State resident