>Does anyone have a tuned input mod for the Clipperton L? I have heard all
>you need is a 2:1 unun.
I agree with Phil Clements.
>Any other things to look out for with these amps. I am think about buying
>one. Any other good mods?
>
>Mike
>W0MU
--- Foreign-made 572Bs appear to have higherVHF amplification than the
American-made originals. Some users who re-tubed, have reported VHF
instability problems. Common symptoms of VHF instability are
intermittent tank arcing and/or a filament that breaks and falls in
pieces to the bottom of the envelope. The fix is to install better VHF
oscillation suppressors.
--- Another area of concern is switching speed. The factory relay is
slower than modern radios. This results in hotswitching--which is a
fairly reliable way of starting a VHF parasitic oscillation. A suitable
high speed switching circuit is shown in "The Nearly Perfect Amplifier"
[QST magazine, 1/94]
Rich---
R. L. Measures, 805-386-3734, AG6K
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