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Re: [Amps] FW: Tuned input

To: amps@contesting.com
Subject: Re: [Amps] FW: Tuned input
From: Roger D Johnson <n1rj@adelphia.net>
Date: Tue, 24 Jan 2006 13:51:09 -0500
List-post: <mailto:amps@contesting.com>
Phil Clements wrote:

>  If one wants to depart from the traditional Pi input network a parallel
>  L/C configuration can be utilized. A tapped fixed inductor from the
>  cathode(s) to ground, shunted by 300 pf Arco trimmers for each band. This
>  seems to cover all bases, is easy to construct, install, and tune. This is
>  the scheme utilized in the Alpha 77 series amps that results in a clean
>  signal and a happy exciter.

This would work fine when the input Z is near 50 Ohms (which most are). 
I think you would need a lot more than 300 pf to get the proper Q on
the lower bands.

73, Roger

-- 
Remember the USS Liberty (AGTR-5)
http://ussliberty.org/
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