[Elecraft] K2 automatic tuner

[Don Wilhelm]

Knut and all,

I do agree with that *and* if the band is 40 meters *and* if the KPA100 
is not the latest design T/R switch it is entirely possible that there 
could be a spurious response above the 40 meter band during the time it 
takes to do the antenna tuning - this may cause the ATU to tune the 
antenna somewhere above the 40 meter band.
There is also the possibility that RFC10 (on the back of the SO-239 
jack) is coupling with the base K2 - and that condition is worse if the 
shield is the older one with a wide notch above the SO-239 jack and no 
solder lugs from the SO-239 jack to the top of the shield.  I am not 
saying that the problem is restricted to 40 meters, only that it is more 
apparent on 40 than on other bands.

If the KPA100 has the older red core toroids at L15 and L16, it should 
be updated with the KPA100MDKT because that mod was created to address 
exactly that problem.
If the shield needs updated, the KPA100SHLDKT is available.

73,
Don W3FPR

On 7/20/2016 2:38 PM, ab2tc wrote:
> Hi all,
>
> I can think of one other *possible* explanation, although far fetched. If
> the K2 transmitter has excessive harmonics or parasitics, this could happen.
> The out of band energy is readily absorbed by the dummy load but not by the
> tuned load presented by the LDG tuner. The antenna analyzer should easily
> resolve this.
>
>