Posted by
Don Wilhelm-3 on
Jul 21, 2006; 4:40pm
URL: http://elecraft.85.s1.nabble.com/KPA-power-fluctuations-tp392338p392340.html
Thorsten,
If I recall your original description, that high power glitch is a result of
the 'attack time' delay in the power control circuits.
Yes, I do believe there is a firmware oversight - the power leveling
controls must change (to compensate for the gain variations) when switching
from band to band, and when on 10 meters, the transmit chain gain is low, so
the power controls are set for a higher level - when going directly from 10
meters to 160 meters (where the transmit chain does not need as much drive),
the control circuits are still primed for the higher drive level and will
drive hard until the power output is actually measured by the microprocessor
the drive level decreased accordingly.
The alternative is to always reset the power drive to a very low setting
when changing bands and build up to the requested setting in a few dot times
of power output. I believe some of the past firmware releases actually did
it that way.
Perhaps if you ask Wayne about it, he may consider doing something different
for the next firmware release - your operating situation (overdriving a
linear, etc.) may be important pieces of information in helping Wayne decide
which method of power initialization is the better one. Right now it seems
like the power drive level is not changed when switching from band to band.
73,
Don W3FPR
> -----Original Message-----
>
> I still think there are some oddities (firmware bug?) in the K2
> ALC algorithm. I still haven't figured out why I sometimes get
> 170W out on 160m.
>
> Torsten
> N4OGW
>
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