A while back W9CF (or someone) posted a message that included the following
link:
http://fermi.la.asu.edu/w9cf/index.html
There is a list of interesting topics, and down in the lower part of the
list is a topic about using a tuner and a balun with open wire line. The
discussion is fairly technical but the bottom line is that making this kind
of setup work well is tougher than we might think. Despite the fact that
most of have used this configuration, and have been relatively happy, there
are all kinds of gotchas that I had never thought about.
It is worth reading.
After you read it you need to go out and put up your antenna anyway because
if you don't then you won't make any QSOs.
------------------ Wes Attaway (N5WA) ------------------
1138 Waters Edge Circle - Shreveport, LA 71106
318-797-4972 (office) - 318-393-3289 (cell)
Computer Consulting and Forensics
-------------- EnCase Certified Examiner ---------------
-----Original Message-----
From: towertalk-bounces@contesting.com
[mailto:towertalk-bounces@contesting.com] On Behalf Of Jim Brown
Sent: Monday, January 26, 2009 12:14 PM
To: towertalk@contesting.com
Subject: Re: [TowerTalk] Window line and Balun
On Mon, 26 Jan 2009 10:57:33 -0500, Tim Holmes wrote:
>the shack was instantly flooded with RF,
The fundamental cause of your "RF in the shack" is common mode
current on the feedline. The cure for that is a good common mode
choke. Unfortunately, it isn't practical to choke ladder line, you
must wind the choke using coax on one or more ferrite cores.
To understand this, study http://audiosystemsgroup.com/RFI-Ham.pdf
and the Power Point presentation about Coaxial Chokes on
http://audiosystemsgroup.com/publish
73,
Jim Brown K9YC
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