Thanks to all of those who offered suggestions to remedy a Collins
30L1 tuning problem. My main concern with the initial query was
determining whether or not a bad tube could cause serious impedance
mismatches that would ultimately effect the loading capacitor
sequence. Some suggested changing several of the obvious parasitic
components in the plate circuit;and only then consider the tubes for
replacement. Cleaning up the bandswitch controlling the additional
banks of loading capacitance made equally good sense. I'll do that
and save the tube replacement for last. Again, what I found odd was
that resonance on 80m was with minimum (zero)antenna tune capacitance;
and on 40m there there was full loading (meshed) capacitance. I found
that somewhat unusual for an antenna matching design. I'd expect some
partial value of capacitance on that control. Some individuals took
issue with the fact that I expected some detuning (or reduction of
power) when rotating the antenna tune control. Perhaps my choice of
words was no clear. I mentioned the "dip" with the antenna tune
control to indicate I was at the extreme ranges of capacitance on each
of the two bands tested. Thanks again to all who took the time to
share their thoughts. It was very much appreciated. Best regards Ron
W2CQM/3
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