[Elecraft] rf power fluctuations

[Stewart Baker]

Hi Frank,

You might like to search the Elecraft Email List User Group for references to
R98.
There are a lot of mails concerning changing that resistor value to reduce the
basic K2 power jumping. Things of course worsen with the KPA100 fitted.
I changed my R98 from 270 ohms to 1k, and it made quite a difference.
It reduces the overall gain in the BFO ALC loop.

73
Stewart G3RXQ

On Mon, 5 Dec 2005 09:04:21 +0100, Frank DL4KQ wrote:
> G`day,
>
>
> I`m running a K2 + EC2(KAT100/KPA100), fully loaded, actual fw`s, which
> seemed to work fine.
> But driving an external linear amplifier (tune situation) I noticed
> inacceptable rf output fluctuations of the KPA100.
> (measured on antenna as well as on dummy-load)
>
>
> K2 (alone): obviously no output fluctuations
> K2+KPA100 (independant of KAT100 settings: bypass or auto mode):
> 1. jumping output fluctuations of 10 to 15 W on all bands
> 2. height of fluctuation nearly independant of K2 power knob setting; f.e. 10
> W jumps at 30 W as on 50 W or any other driver setting.
> 3. fluctuation depends on K2 power knob setting, there exist ranges with and
> without fluctuation (on same band), obviously different ranges for different
> bands.
>
>
> Asked a friend to come along with his K2+EC2 (also fully loaded, actual fw`s)
> for test changing of components.
> But his K2+EC2 showed same behaviour.
> Btw, another K2/100 + KAT100 (all but KX60V options) showed same behaviour
> but fluctuation was less (max. 8 W).
>
> 10-15 W jumps are a bit "much" ...   :-((
>
> Any ideas?
>
> Frank, DL4KQ
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