Here a question on pi filters.
First of all I have to declare that I do not know very much about the
theories on pi/piL filters. I am quite lazy and usually use the empirical
cut and try method. Measuring output and harmonics with a spectrum analyzer
I tried to find a combination of good output and relatively low harmonics. I
understand from the very lively discussion that has been on this reflector,
that there are quite a number of guys who know very much of the theory
behind these often used circuits. Therefore I expect to get an expert answer
to my, maybe, naive question:
In order to get a good effiency on 28 MHz why not lower the anode impedance
by inserting an inductance beetween the anode and filter? I see an example
in my 1991 ARRL HANDBOOK an example:
A tube with 3500 ohms anode impedance and 10 pF output capacitance is
transformed into 1481 ohms and 16 pF by inserting a 1 uH inductance beetween
anode and output filter. Will this inductance act as a parasite choke as
well?
Prosit de Hans SM5KI
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