Peter's question about 75-baud brought to mind something I've been pondering
for a while....I'm not convinced that the "MMTTY + UART" is always optimal from
a timing perspective, though it probably is much better than EXTFSK by
itself. The question in my mind is that since MMTTY is pacing the characters
every ~165ms you are still at the mercy of it's timing jitter at the character
level. There are more than a handful of people with strange or varying stop
bits, including many big-gun contesters. My hunch is that this is a result of
MMTTY's "pacing" not being completely stable or accurate in some systems or
configurations out there in the wild, but maybe it's something else. Surely
this matters to pseudo-synchronous demodulators that rely on tracking the
start-stop bit timing to get a bit more SNR than asynchronous demodulators. I
suppose how much is going to depend on the demodulator implementation at the
receiving end.
Anyway, I'm curious if anyone has another explanation for the funny-stop-bit
phenomenon.
Andy K0SM/2
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