[Elecraft] KPA100/KAT100 trouble

Chris Kantarjiev cak at dimebank.com
Sat Sep 22 15:59:16 EDT 2007


I may be having my first run-in with lightning damage.

A thunderstorm rolled through the SF Bay Area last night. I didn't
disconnect my antennas until I *saw* the first lightning flash. 

Oops, I think.

I turned on the radio later in the evening, and was getting very
high SWR indications on the KAT100, and HiCur on the K2. Hitting
TUNE caused a lot of clicking and clacking, and eventual tune to
about 1.5:1, but SWR was still high on transmit - and the indicated
power on the bargraph was lower than dialed in. This is on both
antennas - a vertical and OCF dipole - both more or less resonant.

I turned off the rig and called it a night.

This morning I pulled out my LP200 dummy load/power meter. The ATU
tunes it to 1.1:1. Power out does not change appreciably
in response to the POWER knob - if set for any value less than 10W, 
the power is about 4W; if set for values about 10W (PA on), power 
out is always about 30W. In neither case is the LED indication on
the K2 correct.

I also notice that the SWR LEDs no longer display anything when the
power is set below 10W, but indicate as expected when POWER is
above 10W.

If I put the ATU into CAL mode, which I understand removes all the
LC network, the SWR LEDs indicate 5:1 (all on), and the power out
is higher, but still doesn't respond to the POWER knob: 10W on
LOW mode, about 90W in HIGH mode.

Connected to the K2/KAT2 (with the serial cable disconnected) the K2
operates as expected (once I remember to turn the ATU back to AUTO :-)

I'm not even sure where to begin looking, but it certainly seems
that the SWR bridge might be malfunctioning.

Help?

Thanks!

73 de chris K6DBG


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