Whoops . . . sent this to Ron but meant to send it to the list :-\
-------- Original Message --------
Subject: Re: [TowerTalk] ladder line
Date: Thu, 19 Apr 2007 19:05:42 -0400
From: Steve <steve65@suddenlink.net>
To: Rob Atkinson, K5UJ <k5uj@hotmail.com>
References: <BAY113-F29A5E66CDA8AF980C22DF98E570@phx.gbl>
I did the banana plug thing, except I put them on the inside so I can
disconnect without going outside.
You might want to determine antenna feed point impedance on the bands of
interest and then use the TLW software from the antenna handbook to
determine loss in the feedline due to mismatch. That information will
allow you to make an informed judgment with respect to loss due to
mismatch and what you are willing to do to lessen it.
Steve, K8JQ
Rob Atkinson, K5UJ wrote:
> First, let's make sure we're talking about the same thing:
>
> Ladder Line = Parallel wire line spaced every 12 to 18 inches with ceramic
> or plastic spreaders. Usually wires are 3 inches apart. Z = 600 to 800
> Ohms.
>
> Window line = Parallel wire line encased in plastic to make a flat plastic
> strap that has rectangular holes cut in it between the wires. Wires are
> usually 1 or 1 1/4 inch apart. Z usually 450 ohms.
>
> Open wire feedline = Parallel wire line with no spacers, wires usually taut
> and suspended and held by pole supports and tower standoffs holding
> insulators the wires pass through. Z depends on space between wires and
> wire gauge.
>
> I solved the lighning problem (I hope, and I hope I never get tested) by
> putting banana plugs on the ends of my ladder line wires and banana jacks in
> my basement window where the line enters. When I'm not operating I pull the
> outside line out of the jacks and away. This works for me because I don't
> do any activity that requires operating during thunderstorms. there's a
> photo of this on my qrz.com page.
>
> rob / k5uj
>
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