Topband: Key Clicks

[Earl W Cunningham]

Tom, W8JI wrote:
 
"Many radios (not just Ten Tec) incorrectly display the CW rise and fall
times, so check the radio on a scope.
 
The FT2000 is an example. It displays (like many other radios) twice the
real rise and fall time. If you set the radio for 3ms, it is really 1.5
ms."
==========
How true!  And the Icom IC-756pro3's CW rise/fall times have been
measured to be actually half of the menu setting.  The factory default of
4 msec results in a very clicky 2msec.  The IC-7800 is exactly the same.

Therefore I have to disagree with the E-mails saying that the clicks are
caused by overdriving/ALC (although this will surely accentuate the
clicks).

Another ham said he had his friends listen for clicks from his IC-7800
with the factory default setting of 4 msec and that they reported it to
be "clean."  But....did he instruct his friends to use a narrow CW filter
and then tune just outside of their receiver passband listening for the
clicks?  As Tom points out, this is the correct way to check for clicks.

The IC-7800 has clicks at least +/-3 kHz with the factory default setting
of 4 msec (really 2 msec).  At the menu maximum of  8 msec (really 4
msec), the clicks are reduced to +/-300 Hz.

73, de Earl, K6SE