On Tue, 30 Mar 2010 09:19:15 -0400, Carl wrote:
>Those are fairly common for multi TX stations to knock down harmonics and
>phase noise.
Yes. I'm currently working on a Q&A style tutorial on coax and stubs. The
first draft is at http://audiosystemsgroup.com/Coax-Stubs.pdf
Comments are appreciated. I would especially appreciate additions to the
table of amps and output circuits.
W2VJN's book is excellent, and worth the money if you're doing any sort of
multi-transmitter station. Available from Inrad (the crystal filter people)
for $20. There are also four excellent pieces in QST written by Ward
Silver, N0AX. They are cited in my tutorial. And George has contributed
some of his work on stubs to the 2010 ARRL Handbook.
As to the effect of a stub on the current waveform -- a proper stub (or
combination of stubs) should be invisible at the TX frequency, but a short
circuit at even order harmonics. If the amp has reasonable output filtering
without the stub, the stub should have no significant effect on that
current waveform.
73,
Jim Brown K9YC
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