[Elecraft] KPA100 "New Shield" & still getting RF

[George Winship]

Tom N0SS wrote;

    A few KPA100's have demonstrated some instability (often on 40M). =
The instability is generally evidenced by a high SWR (esp. if the KAT100 =
is in-line... all leds light!!!).....

    This has been driving me nuts. I installed the new shield during the =
original assembly of the KPA100.  Here is what is happening;

    If the KPA100 is removed from the K2 and set beside it with all =
cables still attached there is no problem. The KAT100 is also still =
in-line under the K2.

    If the KPA100 is mounted on the K2 with the KAT100 in-line here is =
what happens; If the antenna is already reasonably matched ( SWR 1:5 to =
1) it works fine in the cw mode. On SSB all leds light , modulation =
ceases, and output stays steady at 100 watts or more or whatever power I =
have set 11 watts or more. If I am trying to tune an antenna that has a =
significant mismatch (eg. tuning an 80m ant on 40), any output cw or SSB =
11watts or higher will cause complete shut down of the radio and power =
supply. This occurs with the KAT100 in AUTO or BYPASS mode.

    If the KAT100 is taken out of line and ant. run directly to KPA100 =
it works fine.=20

    I have tried running the KAT100 on a different ps. Same results. I =
have checked and checked again to make sure all panels are grounded. The =
frequency counter cable is removed from the K2. The KAT100 "tunes" any =
antenna I have on any band without any problem except on 40m where this =
problem occurs. There seems to no problem on 40 if the KPA100 is turned =
off. There is also no problem if I tune into my 50 ohm dummy load.

    And finally, can someone tell me how I can GET RID OF "MURPHY".  Not =
only do I have this problem, but many times the engine in my truck quits =
when I use the turn signals(seriously), my 2m mobile sometimes works, =
sometimes doesn't, my HF mobile takes spells on whether it wants to =
recieve or not, and the last time I tried to use spectrogram it wouldn't =
"hear" my signal, so I had to set my filters by ear.

    Thanks for any suggestions.

73,

George, NC5G  K2/100 =20


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