[Elecraft] K3S current draw relative to KAT3A settings

[Nicklas Johnson]

On Tue, 12 May 2020 at 11:51, Joe Subich, W4TV <lists at subich.com> wrote:

>
> > So I guess the question is this: is it expected to see such a large
> > variance in power consumption for the same output power based on the
> > values of C and L for the KAT3A?
> Is the KAT3/KAT3A *tuned correctly*?
>

This came up because the rig is drawing a lot more current on 20m vs 40m,
when the KAT3A is tuned for the antenna (which is a better match on 20 than
on 40).  For the dummy load, no, the KAT3A won't be tuned correctly when I
manually choose values for C and L; I just used it as a way to better
characterize the nature of the behavior that I was seeing and to reduce the
number of variables.  However, as I mentioned, the behavior is similar when
running FT8 with the tuner correctly tuned for the antenna.  If memory
serves, the difference in current draw was something like 6 amps between 40
and 20, though I can go measure that again if an exact value is useful.

You are comparing apples and oranges here.  At 12W the 100 W amplifier
> is bypassed.  At 13W the 100W amplifier is engaged.  The differene you
> see is due to the 100W amplifier.
>

I'm not talking about the difference in measurements in the chart
vertically; I'm talking about the difference horzontally.  I did the
measurements twice deliberately, specifically because PA is
bypassed/engaged, because I wanted to see if there was any relationship
there as well.

   Nick

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