[Elecraft] KAT500 all of a sudden tuning problem

[Robert G Strickland]

I have a K3, KPA500, and KAT500. Antennas are a SkyHawk on 20-10m; a 
sloping dipole on 40m; an inverted V on 80m fed with 450ohm window line, 
a 1:1 current balun/choke, and a short run of RG8 into the radio. This 
setup has been working like a charm until... out of nowhere, neither the 
40m nor the 80m auto tuning works [everything still tunes ok on 20-10m].

On both 40/80m, the auto tuning continuously cycles, ending in an swr of 
99.9:1 and a fault on the tuner. Pressing the TUNE button on the KAT500 
has no effect on the outcome.

On 40m with the KAT500 set to bypass, the K3's swr reading is around 
1.1:1 and the KAT500 something similar, which is reasonable in that the 
40m antenna was cut very carefully to resonance, there are no 
environmental variables that would detune it, and visual inspection of 
the antenna is okay.

On 80m with the KAT500 set to bypass, the K3 swr reading is 47:1 which 
seems unexplainable high, given that the 80m antenna was also cut 
carefully to resonance. However, I can't get up the tower at this point 
[serious biking accident] to inspect the window line or its connection 
to the dipole wires. However, since both 40m and 80m tuning went out 
together, I'm not sure how to interpret the different swr readings on 
the two bands.

Any guesses or leads as to what this might be and/or what else I might 
check? Thanks much.

...robert
-- 
Robert G Strickland, PhD ABPH - KE2WY
rcrgs at verizon.net.usa
Syracuse, New York, USA