On Dec 1, 2006, at 12:16 PM, roy gould wrote:
> Well before and after the contests, the emails and letters were
> short of threatening. RTTY on 160? Are you NUTS!
45 baud RTTY is likely problematic. If you cut the symbol rate in
half, it would be reasonable, although it would take twice as long to
send something.
The cause is intersymbol distortion caused by multi-path propagation.
It introduces small variable delays in each path, which causes the
symbols to arrive at slightly different times. The further away you
get from the MUF, the worse this problem gets.
This is why 31 baud PSK works on 160, but 45 baud RTTY does not do so
well. And why 300 baud packet works on 20m, but not on 80m.
Bill Coleman, AA4LR, PP-ASEL Mail: aa4lr@arrl.net
Quote: "Not within a thousand years will man ever fly!"
-- Wilbur Wright, 1901
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