This is a little off-topic relative to the Subject line, but extremely relevant
to enjoyable Topband operating:
On Dec 30, 2013, at 6:51 38PM, Jim Brown <jim@audiosystemsgroup.com> wrote:
> Fast rise time of the keying waveform is the major cause of clicks. W8JI and
> others long ago identified this as the cause of the FT1000-series rigs awful
> clicks, and fixed them. The rise time of some rigs (notably the IC7600) is
> adjustable, and only the slowest rise time is acceptable.
Add the venerable Kenwood TS-950SDX to the list of rigs with user-adjustable
rise/fall times. And -- as Jim notes -- only the slowest rise time is fully
acceptable, despite the pains Kenwood took to carefully "shape" those RF
waveforms during their "on" and "off" transition periods.
In the case of the 950SDX, the user can select nominal rise/fall times labeled
2, 4, 6, or 8 milliseconds (ms) from one of the configuration menus accessible
via the front panel MENU options. A few years back, in extensive tests on a
daytime 80-m band with an equally fanatical friend listening critically, we
determined that -only- the 8-ms setting was "clean" with respect to click
generation. Probably the 6-ms setting would be marginally "OK" if the
transmitted signal were not loud anywhere, but since my usual objective when
chasing DX on 160 is to be as loud as I can, 6 ms is not really an acceptable
solution for maintaining good relations with my close-in Topband "neighbors"
here on the east coast of North America. Once we ran those tests, I set the
TS-950SDX menu choice to 8 ms, and I've not changed it since.
Bud, W2RU
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