>10 meters acts strange. The output oscillates as does the VSWR--not a fast
>one but noticeable on the power meter. If I drive the amp hard enough the
>relay in the amp will drop out and begin to oscillate as well. Any ideas
>on this one?
I am sure Rich will jump on this one so I hope I don't steal his thunder:
It sounds like your amp has an oscillation on 10 meters. This can happen
when the parasitic suppressor resistors get old and change in value.
Pull the supressor resistors at the anode out from their coils (just
disconnect one end) and measure the resistance. Normally these are in
the 50 to 100 Ohm range. You've probably got a high impedance due to
blown or failed resistors. If the resistors are OK, you've got other
problems that I'll let Rich address, but my hunch is they are bad.
Rich sells some real good Matsushita's that are excellent for this
purpose.
Why don't you see this on other bands then? Well, the amp is less stable
at 30 MHz than say 7 MHz due to the parasitic inductances in leads, etc.
This tends to make the amp more prone to oscillation unless proper
supression is applied.
73,
Jon
KE9NA
-------------------------------------
Jon Ogden
KE9NA
http://www.qsl.net/ke9na
"A life lived in fear is a life half lived."
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