Excellent, detailed and informative posting, Lee - thanks for another view
of this interesting topic.
It seems that there are two major keying differences between your TT
Jupiter and my Icom PRO: (a) your radio takes 20 msec to transition from
receive to transmit and mine takes 10 msec; and (b) your sidetone is time
synch'ed with the r-f output while mine is not.
So, your dot shortening effect, when used with TT circuitry only, is worse
than mine as speed increases, but your sidetone accurately portrays the
weighting of the r-f output at all speeds while mine does not.
Excellent procedures and good detailed results that we can interpret and
Considering that both the Jupiter and the PRO are DSP-core-based radios,
you would think that the firmware could make speed-related corrections for
the dot/space ratio and compensate for the higher-speed shortening.
And I would think that Icom could certainly postpone the start of the
sidetone keying until the transmit state has been attained so that the
sidetone would accurately reflect the output signal weighting. That is
precisely what happens with non-QSK operation: the two signals are
perfectly time-locked so that what you hear is what you are sending.
And there is no reason on Earth why Icom cannot provide for weighting
adjustments on a menu, etc. They give you a "ratio" adjustment but that is
Thanks very much for you posting, Lee. I think that we all now better
understand a little more about our radios and how they work. Sorry about
snipping most of your excellent posting, but I wanted to save the
72/73/oo, George W5YR - the Yellow Rose of Texas
Fairview, TX 30 mi NE of Dallas in Collin county EM13qe
Amateur Radio W5YR, in the 56th year and it just keeps getting better!
QRP-L 1373 NETXQRP 6 SOC 262 COG 8 FPQRP 404 TEN-X 11771
Icom IC-756PRO #02121 Kachina #91900556 IC-765 #02437
All outgoing email virus-checked by Norton Anti-Virus 2002
> There are [or have been] several interesting threads running which
> seem to be slowly converging into a good discussion of keying
> characteristics of Pegasus/Jupiter [PJ's for short], Omni VI+, Icom
> 756Pro and also some general comments regarding key clicks, etc.
> The thing I find interesting about the latest round of discussions is
> that we are beginning to take the subjectivity out of the discussion
> and are looking at some numbers that describe what we are hearing.
> So in that spirit, I decided to run some tests on my PJ's much like
> George, W5YR has been running on his Pro. In short, the PJ's look
> pretty good. Perfect? No, but pretty good when held up in
> comparison to the rest of the pack.