> My references come from the professional literature and work on DSP
> windowing. 7 ms is OK for very slow Morse code, 2 ms just about right for
> 20 ms contest dots.
CCIR standards and the FCC, which the CW keying section in the
Handbook is based on, say:
2ms rise and a fall is good for 100 WPM or so in a K5 (fading)
circuit and 150 wpm in non-fading circuits.
5 ms is good for 35 WPM fading and 60 wpm for non-fading
conditions.
7ms is good for 25 wpm fading and 45 wpm non-fading.
There was no detectable difference in copy of my signal when I
switch from ~7ms to ~2 ms when my signal was at noise floor in
VK on 160 meters, while I was sending about 25 WPM with 55%
keyer weight.
I've never heard anyone use 100 wpm on noise-floor signals, or 150
wpm with strong signals, although I have to admit I can't copy that
fast so I might have missed some QSO's at that speed.
73, Tom W8JI
W8JI@contesting.com
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