[Elecraft] K3: SWR meter readings on 10m..mystery solved...

[VK7JB]

I've solved my mystery.

I read in the archives that the KAT3 ATU is not completely out of circuit in
"bypass mode".  If I understand correctly, small values of L and C are used
to remove it functionally, but there is stray reactance that might
contribute to the higher indicated SWR on some bands.

So then I wondered if the KAT3 might need to be tuned at least once into a
50 ohm load for the "bypass" state to be correctly determined.  Made sense
in my imagination, and thinking on it,  I realised I'd never tuned the ATU
into a 50 ohm load before.

So I did that - tuned the KAT3 to the dummy load on the bands where it
previously indicated higher than expected in ATU bypass mode.  I let it do
its stuff and find a match for the dummy load, then bypassed the ATU.  

Now, in ATU "Bypass" mode, the K3 reads 1.0:1 SWR into the same dummy load
that it previously showed as 1.5:1.   Issue gone.

73,
John
VK7JB



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