[Elecraft] K3 - SWR on Tx Gain Calibration

[Geoffrey Downs]

For some time I've been puzzled that, when doing a TX gain calibration 
either manually or with the utility, the SWR displayed was 1.0:1 on all 
bands except for 10m where it was 1.5:1. Yesterday my K3 (Ser. No. 266) had 
a meeting with a K3 (slightly earlier Ser. No.) belonging to David G4DMP 
(the owners met too!) and we found that his K3 was the same.

Now here's the interesting thing. During tx gain calibration a 50 ohm dummy 
load is used and the ATU is in bypass mode. As an experiment David put his 
K3's ATU in circuit on 10m and pressed ATU Tune - result (unsurprisingly) 
1.0:1. He then put the ATU back into bypass mode and held Tune as one would 
do in a tx gain calibration. Hey presto - 1.0:1! My K3 behaved in exactly 
the same way and now always displays 1.0:1 on 10m into the dummy load with 
the ATU in bypass mode.

Presumably this is something to do with the ATU not being out of circuit 
when in bypass mode.

73 to all
Geoff
G3UCK