Good Day All,
A stupid question to many, no doubt, but one that I'd like some clarification
on, at long last...
Specifically, anything that I've read in different literature & in on-line
write-ups regarding the proper tuning of grounded-grid linear RF amplifiers
makes note of one, final step in the tune-up procedure: specifically, one is to
reduce the plate loading capacitance (and thereby slightly over-couple the
amplifier to its load) such that power output is lowered by some 5-10%...
Correct?
Yet, nowhere is this instruction followed by anything advising one to
subsequently "re-peak" the plate tuning capacitor in kind, as I instinctively
always do (force of habit, I guess).
Is it a requirement to do just that, i.e. to tweak the plate tuning after this
deliberate over-coupling...? Have the authors of these write-ups simply assumed
that that is, indeed, the case, & have therefore not made specific reference to
this process...? Or does one truly advance the loading capacitor to lower
output---and then leave well enough alone...?
I ask this because I am finding that the tuning requirements of my homebrewed
2x813 kilowatt can be VERY exacting: improperly adjusted, & the keying from it
on CW can sound inordinately hard---almost clicky. I'd like to do things right
with it, both for the sake of the tubes, as well as for others on the band who
might be operating close to my frequency...
Thanks in advance,
~73~ de Eddy VE3CUI - VE3XZ
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