>
>
>I have an SB-221, to which I added 10m, and also performed the
>input circuit changes per AG6K mods. Now have very low VSWR on all bands.
>Either as a coincidence, or result, I now have the TUNE
>variable cap arcing when tuning over 500w.
>Any thoughts why this happens and how to correct?
>Seems to do it on more than 1 band.
>Thanks in advance,
>Bennett ko2ok in NJ
>
The Tune-C in a 220/early-221 typically has a withstanding ability of
over 3500v. The actual peak RF potential on ssb is around 2600v. Unless
the Tune-C has melted and/or bent plates, arcing should not be taking
place. If the Tune-C looks ok, and intermittent arcing is taking place,
my guess is that the amplifier is intermittently oscillating c. 110MHz.
Rich. Measures. Web site: www.vcnet.com/measures
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