On 3/12/2024 2:40 PM, Robert W5AJ wrote:
Best I can tell, FTdx10 CW with 6ms rise time is in par with K3 looking
at QST In Depth review
Fast rise time CAUSES clicks; beginning with the first K3, Elecraft uses
a carefully shaped keying waveform that they call "sigmoidal," (which
I've heard described as a raised cosine) to provide nice sharp keying
without clicks. I've heard that after a bad ARRL review for for their
6500 series rigs, they adopted that shaping or something like it.
But rise time is the wrong thing to measure -- a spectral plot showing
sidebands with a string of dits shows where the bodies are buried.
Likewise, modulation with a sine wave, or even an IMD pair of sine
waves, fails to expose splatter caused by processing like Yaesu is
(was?) doing in those rigs.
Splatter running VHF/UHF rover is far less likely to cause QRM except
during band openings on SSB.
FWIW -- I love my K4, but am still quite happy with my 2008-vintage K3
with upgraded synth.
73, Jim K9YC
It is interesting to watch the CW signals now with the BandScope
more so during CW contest!
Still own the K3 but I'm not likely to sport (Buy) a K4
The FTdx10 is ideal rig to carry on the 50Mhz rover trips, gets me band
scope & built in sound card
73 Robert W5AJ
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