>I'm pretty clueless about such matters, and would appreciate any advice.
>
>What do folks think about the importance of, and/or utility of, installing
>the
>EBS-1 electronic bias kit in an AL-1200 that is going to see heavy duty
>contest use?
>
>At the risk of demonstrating to the world my complete lack of undestanding
>of high power amplifiers, is it correct that this kit basically senses input
RF,
>and biases the tube to cut-off in the absence of input RF - thus reducing the
>"circulating currents"?
*** With no input RF, there is always zero RF circulating current, no
matter what type of bias switch is used.
-- . When SSB RF drive drops below the EB-switch threshold level
during soft-syllables, the amplifier switches in and out of non-linear
bias. This results in more IMD during soft-syllables. Another problem
with RF-actuated bias switching is that there is no headstart for the
amplifier's RF relay contacts to close before RF arrives. This results
in hot-switching the RF input relay and the RF output relay in the
amplifier. For AM and FM modes, RF-actuated bias switching does not
switch during soft-syllables, so there is no added IMD, although the
hot-switching problem still exists.
>
>Thanks!
>
> ***dan, K6IF
Rich, AG6K, 805-386-3734, www.somis.org / new e-mail adr r@somis.org
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