11 Jan
2014
11 Jan
'14
7:15 p.m.
At 07:07 PM 1/11/2014, Paul Koning wrote:
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.
73,
-Rick (K1MU)