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Re: Topband: 300 ohm twin lead for bidirectional Beverage antennas

To: topband@contesting.com
Subject: Re: Topband: 300 ohm twin lead for bidirectional Beverage antennas
From: Mike Waters <mikewate@gmail.com>
Date: Fri, 28 Feb 2020 18:02:48 -0600
List-post: <mailto:topband@contesting.com>
Hi Joe,

The control boxes that you can buy are usually optimized for ~450 ohm line.
Thus, they need custom transformers at each end. I wouldn't label that as
undesirable, but that might be part of why some folks say that it is.

Most 300 ohm TV twinlead that has been long used for rooftop antennas is
flimsy and might break from flopping around in the wind. I am not aware of
a rugged 300 ohm line. Plus, when it gets wet --or worse yet, covered with
ice or snow-- its impedance changes drastically enough to seriously affect
your F/B ratio.

But those same things can be true of ladder line!

73, Mike
W0BTU

On Fri, Feb 28, 2020, 2:20 PM Joe Giacobello, K2XX via Topband <
topband@contesting.com> wrote:

> I'm considering putting up two bidirectional Beverage RX antennas.  It
> appears that most of the recommendations for Beverages consider the
> close spacing of 300 ohm twin lead undesirable for reasons that are not
> entirely clear
>
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