By the way, just because the occupied bandwidth of RTTY is in the region of 250
Hz to 270 Hz (depending on the number of stop bits), it does not mean that you
can fit 10 RTTY signals into a 2.5 kHz passband.
You cannot.
As I mention in my previous posting, the "occupied bandwidth" number is purely
a formal number for FCC purposes. (I also don't know what other countries'
rules are like.)
The 0.5% number on each side of a signal is still a very signifiant amount of
power. By definition, a 1 kW station is still putting out 10 watts worth of
QRM outside its "occupied bandwidth." A strong RTTY station that is close to
your location will render DX completely gibberish if you try to squeeze the two
of them into adjacent 250 Hz channels.
Nudging to within 100 Hz of a band edge is not the same as nudging one of your
RTTY carriers to within 200 Hz of another RTTY signal's carrier. With the
former, the FCC won't zap you because you are working within the rules. With
the latter, however, you might get a nasty message on your screen :-) :-).
73
Chen, W7AY
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