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Re: [TenTec] Ten Tec 229 Tuner on 160M

To: "Bob McGraw - K4TAX" <RMcGraw@Blomand.net>,"Bwana Bob" <wb2vuf@gti.net>,"Discussion of Ten-Tec Equipment" <tentec@contesting.com>,"wb2vuf@arrl.net" <wb2vuf@arrl.net>
Subject: Re: [TenTec] Ten Tec 229 Tuner on 160M
From: "Jim Brown K9YC" <k9yc@audiosystemsgroup.com>
Reply-to: Discussion of Ten-Tec Equipment <tentec@contesting.com>
Date: Sat, 08 Dec 2007 10:21:45 -0800
List-post: <mailto:tentec@contesting.com>
On Sat, 08 Dec 2007 08:18:02 -0500, Bwana Bob wrote:

>hanks, Bob

>Yes, my coax-fed 80m dipole only works on 80m and its odd harmonics. 
>That's why I'm planning to switch to balanced feed. After reading the 
>material on W2DU, Walt Maxwell' site, I'm going to try a ferrite bead 
>current balun with a short run of coax to the tuner.

Several suggestions. First, consider a FAN dipole, which is very easy to 
build and works really well with coax. My 80/40 fans work well on 30M and 
17M too. 

Second, study my material on coax chokes (current baluns). It's a 25-year 
later expansion of Walt Maxwell's work using toroidal cores to wind multi-
turn chokes that provide FAR better choking of the feedline. This has the 
advantage of signficantly reducing noise picked up on the feedline as 
compared to Walt's "string of beads" chokes. BTW -- Walt has read my work 
and says he likes it.


To reduce the feedline noise, the choke MUST be at the antenna feedpoint. 
You can't wind a current choke with twinlead -- it MUST be wound with coax. 
You COULD use a small section of coax with that choke, then transition to 
twinlead if you wanted to. That would work. 

Another point re: an earlier post in this thread. It has been shown (in an 
excellent piece of research published in one of the ARRL Antenna 
Anthologies) that conventional window line is rather lossy (worse than coax) 
when it is wet. Cutting the windows as was described reduces that loss. 


Jim Brown K9YC

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