At last....
Tom, W8JI has begun to rebuild his web site. And one of
the first posts he has put up is about key clicks with a
discussion of "correct" rise and fall times and the overall wave
shape. The site goes on into a lengthy description of
how to modify an FT-1000MP to improve the CW keyed
wave shape (not easy!).
Most interesting comment he makes is about the rise/fall
times he uses on 160 meters for 30 to 35 wpm, and the weak
signal readability reports he rcvs from far away places:
Tom uses 6-7msec rise and fall times!
Per the Ten Tec Orion wave shape control specs, we will
be able to adjust both rise and fall times out to 10 msec, in
1 msec increments -- that is great!
George, W5YR, has pointed out in previous posts here that
a secondary cause of keying problems that can generate
keying artifacts at least as bad if not much worse than the
total rise/fall times, is what happens near the max of the
CW waveform; that is at the transition from the rising
slope at the top of the envelope to the actual "flat top",
and from the flat top as the curve starts down the fall time
slope. Tom discusses this just a little.
W5YR has said this effect is capitalized upon with so-called
"raised cosine" keying waveforms which have very gentle
"slow" transitions and are noted for generating a minimum of
keying artifacts.
We don't yet know about the Orion CW waveform in all its'
detail just yet, hi.
If interested, among Tom's new pages is the following where he
discusses some of these click issues:
http://www.w8ji.com/keyclick.htm
73, Jim KH7M
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