[Amps] coaxial stub on amplifier output

[Carl]

IMO, the best ones were written in the NCJ and individual club contest 
juournals by those who actually needed, developed, used and refined them.

Stubs can be designed to work anywhere you want them.

Carl
KM1H


----- Original Message ----- 
From: "Jim Brown" <jim at audiosystemsgroup.com>
To: <amps at contesting.com>
Sent: Saturday, April 03, 2010 11:57 AM
Subject: Re: [Amps] coaxial stub on amplifier output


> 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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