[Elecraft] KAT100 Tuning Failure

[Don Wilhelm]

Jeremy,

Hopefully you had the ATU menu set to CAL for those tests.  If not, 
please re-do the measurements.
Assuming that you were set for ATU CAL, I can offer these comments:
With the configuration you have now - KAT2 and KPA100 out of the 
picture, those results indicate that 1) the KAT100 wattmeter is not 
properly balanced and calibrated, or 2) something in the KAT100 
wattmeter has been damaged - most likely diodes D1 and D2.
It is possible that the diodes have been 'partially damaged' and have 
become frequency sensitive.
With a dummy load connected and the ATU menu set to CAL, you should have 
a 1.0 SWR on all bands.
The fact that you do not says that either the wattmeter is not properly 
balanced, or one or both diodes are bad, or that there is some random 
L/C element stuck in the path to he dummy load (that would be a relay 
problem).

I would arbitrarily replace D1 and D2, and then attempt to balance and 
calibrate the KAT100 wattmeter as indicated in the KAT100 manual.
If you cannot achieve a good null when balancing, just stop - attempting 
further steps is futile until you can obtain a good null.

73,
Don W3FPR

On 7/20/2015 7:15 PM, JeremyJones wrote:
> Ok, so I've removed the KPA100 completely, and disconnected the KAT2 serial
> and RF connections.  I connected my W2 watt meter on the output of ANT2 of
> the KAT100, and the LOAD side of the sensor to a 50 ohm dummy load.  The
> readings and indications I got are as follows:
>
>