Dave: The answer to your question is, I believe, the choke impedance
should be as high as you can make it. Typical R.F. chokes have series
and parallel resonances which must be dealt with. A parallel resonance
at the operating frequency can be very useful, providing a high
impedance to isolate the power supply from RF and achieve minimum
loading of the normal tuned circuitry. A series resonance at the
operating frequency is bad news, usually resulting in a burned up choke.
A multiband amplifier presents a real challenge to the choke designer
to park the series resonance somewhere between our ham bands. There have
been many posts on this reflector the past few years on this topic. I
have followed the practice of collecting excerpts of interesting posts
into a number of files for my own use. One of my files is devoted to RF
chokes. It is about 5 pages long and I will send it to you if you wish.
73, Dan, N5AR
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