On Thu, 28 Aug 1997 18:06:26 +0000 "jeg" <jackg@one.net> writes:
>I had a Kenwood TS-922A that had a bandswitch arcing problem.
>Keying the amp while running VOX would result in an arc
>typically once per 20 transmissions.
>Upon investigating, I found that the problem was that the RF input
>and output DPDT relay was a large, SLOW, contactor style relay that
>was energized at the same time as another smaller, faster relay that
>controlled the bias and indicator lights. I replaced the RF
>input / output relay with a P&B 3PDT relay, and used the third
>pole to switch the bias.
>After this change, all bandswitch arcing ceased completely. I
>replaced the burned bandswitch, and never had an arc again over a
>period of about 6 years of use with VOX.
>IMHO, this problem had nothing to do with parisitic oscillations,
>just poor design of the RF and bias switching.
>
>Jack, WB8BFS
A excellent observation and a simple fix...just what we need. Not a few
weeks of BS.
I would still suggest changing the parasitic suppressors but certainly
not mandtory.
73....Carl KM1H
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