[Elecraft] [K3] High SWR when running above 12w on 160,80m

[Bob Wilson, N6TV]

A bad coax jumper or a loose coax connector can cause problems like this,
especially if it is in between the radio and the external SWR meter.  Can
you try a different coax jumper?  Or, can you bypass the external SWR meter
and connect the antenna directly to the K3, perhaps ANT 2 instead of ANT
1?  If no difference, I suppose something could be wrong with the low pass
filters inside the K3, but check the coax first.

73,
Bob, N6TV

On Sun, Mar 3, 2019 at 4:40 AM Ilya <nerevarthelord at gmail.com> wrote:

> Hi Gentlemen!
>
> Recently I got some strange behaviour in my K3/100 #4413, looking for any
> ideas.
>
> When running more than 12 watts on 3.5 and especially 1.8 mhz, the internal
> meter shows higher SWR values. The higher the power is set - the higher the
> showings are. Like when the power is 20w - it shows smth near 2.0, when the
> power is set to 50w - it shows 3.0 and says 'HI SWR'. If I tune antenna
> with ATU prior to transmitting - the values are lower, but overall
> behaviour is reproduced. Everything looks fine on 40 meters and higher.
>
> But:
> 1. External meter shows normal SWR like 1.2-1.5 (the real one - the same as
> my antenna analyzer shows).
> 2. If power level is set lower than 11.9 watts - the problem does not
> persist (internal meter shows 1 or 2 segments).
>
> Given the description above - I guess something should be wrong in the 100w
> amplifier?
> Looking for any advice.
>
> Thanks and 73!
> Ilya, R3XA
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