[TenTec] apparent match possible in T Tuner

[Darrel Emerson]

On the relative efficiency of T-networks vs. L-networks: it's very
instructive
to play with the simulated T-net tuner from Kevin Schmidt, W9CF  on:

http://fermi.la.asu.edu/w9cf/tuner/tuner.html

This is a simulated C1-L-C2 T-network that  you can tune yourself, and
which tells you 
the overall efficiency once you're matched . You can set up your own
component values,
so by making either C1 or C2 extremely large, you can effectively turn this
simulated T-network 
into either a Lo-Z or a Hi-Z  L-network.  All other things being equal,
it's easy to demonstrate on this
simulator that, once  you have a match, the L-network efficiency wins over
the 
T-network.

This T-net simulator is great fun to play with, as well as being very
instructive!

       73
               Darrel, aa7fv.
================================================

Date: Tue, 22 Mar 2005 09:03:12 -0500
From: "Ten-Tec Inc. Amateur Radio Sales" <sales at tentec.com>
Subject: Re: [TenTec] apparent match possible in T Tuner
To: Discussion of Ten-Tec Equipment <tentec at contesting.com>
Message-ID: <6.2.1.2.1.20050322085730.04d833a0 at tentec.com>
Content-Type: text/plain; charset=us-ascii; format=flowed;
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At 09:15 PM 3/21/05, you wrote:

>Do you mean to say you really might not be able to notice that all the RF
is
>just circulating in the tuner with a T match instead of going out to the
>antenna if you get the "false" match? There would be no indication of this
>except nobody would answer you because your signal would be so weak? Does
>that really happen to people???


Jeff - the answer is "sure".  There is no way for you to assure that you've
adjusted the T for the most efficient match.   The beauty of the L network
is
that there is only one possible match for a given load.

A reading of the antenna tuner market survey article that appeared in the
February 2003 QST, page 69 would be a good complement to this
discussion.  It can also be read on-line by ARRL members at:

http://www.arrl.org/members-only/prodrev/pdf/pr0302.pdf

Scott Robbins
W4PA<