On 7/27/2022 12:08 PM, Lyn Norstad wrote:
CW Rise Time set to the default, 4ms (range 2ms - 8ms).
This is MUCH too fast, very clicky. Even the slowest is much too clicky.
See my analysis of ARRL Lab Test results done in 2014. This is all THEIR
data, that they sent me in electronic form.
http://k9yc.com/TXNoise.pdf
Kenwood is the cleanest of the JA transceivers, but the cleanest ones by
a lot are Elecraft K3 and later, where they developed non-adjustable
keying which Wayne has describes as "sigmoidal" or "raised cosine"
shaping. He introduced it in 2007; Flex 6000 series when tested by ARRL
(after my report) was pretty nasty, but they subsequently followed
Elecraft's lead and got a LOT cleaner.
What we CALL CW is really 100% amplitude modulation of a carrier by a
rectangular wave train, and the harmonics from the transition excite IMD
that is heard as clicks. I demonstrated this in another report presented
using Power Point, but not intented as a Power Point talk. It's simply a
convenient way of presenting the data.
http://k9yc.com/FTDX5000_Report.pdf
Slide 13 shows the unmodulated carrier, slide 14 shows an FTDX5000
sending dits at roughly 30 wpm.
I purposely leaked an early version of this report to someone I
suspected would make sure that Yaesu saw it. Within days of my
publishing it, Yaesu released the firmware update documented by later
slides.
The only reason for giving hams adjustable rise time is MARKETING!
BTW -- there are other very slick elements of Wayne's designs that
drastically reduce their transmitted and received phase noise, most of
which date back to 2007 in the earliest K3.
You can see my earlier measurements of a neighbor's 7600 as he varied
rise time. He's a GOOD neighbor; I have another with a 7600 who, for
years, chewed up 10-20 kHz of the band on CW; K6XX and I, both running a
K3 legal limit, 3 miles apart, can work within 500 Hz of each other and
hear each other as simply another loud signal. These data are with the
original K3, long before the improved synth board.
73, Jim K9YC
73, Jim K9YC
73, Jim K9YC
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