12 Jan
2014
12 Jan
'14
5:13 a.m.
On 01/11/2014 10:15 PM, Rick Murphy wrote:
At 07:07 PM 1/11/2014, Paul Koning wrote:
Old style RTTY is around but be careful since most people do it using
computers now the baud rate and
encoding me be incompatable with old TTY based RTTY. That and there
are several RTTY sounding modes
that are NOT RTTY.
That sounds right. As far as I know (from
reading; I wasn't active
in this area) ham radio RTTY was always mostly 5-level code (still
may be, for all I know). The use of ASCII in the mechanical RTTY
days was a minority.
Classic RTTY is still basically 5-level Murray ("Baudot") code with
simple frequency shift keying. There's still a fair amount of that,
mostly showing up in various contests. Almost nobody uses ASCII for
simple FSK teletype in ham stuff. I'd say it's pretty much
nonexistent, even though it's allowed by regulations.
There's a large (probably quite a bit larger than
RTTY) block of
activity using ASCII in various phase shift or multi-tone modulation
techniques that allow reliable communications over marginal RF
transports. Some of these are quite interesting, such as very short
duration atmospheric ionization due to meteors. Oh, and using
airplanes and the moon as reflectors.
Sounds like your talking about PSK31(HF
narrow band sound card digital
mode), WSJT65(weak signal and EME),
FSK441 (Meteor scatter). There are about 20 more modes and rates of
signaling currently in use those were the top three.
Some of those do not directly transmit ASCII, WSJT65 is a good example,
So would HellSchribe.
Allison/KB1GMX