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Re: [TowerTalk] spiderbeam plastic telescope to support Inv V

To: "Alex Malyava" <alex.k2bb@gmail.com>, towertalk@contesting.com
Subject: Re: [TowerTalk] spiderbeam plastic telescope to support Inv V
From: "Dan Zimmerman N3OX" <n3ox@n3ox.net>
Date: Thu, 18 Sep 2008 18:54:26 -0400
List-post: <towertalk@contesting.com">mailto:towertalk@contesting.com>
"What if i use lower 40-50' portion of their 60-footer? Is it gonna say
straight?"

Guyed?  Unguyed?

You won't be able to put much balun up very high, in any case, honestly.
You might consider running ladder line down the pole, an electrical half
wavelength of it, and putting the balun there.  You'll have some extra
ladder line if you're doing the 80m version, but maybe it can continue down
the house or you can loosely coil it on a messenger line.

The poles are overall pretty sturdy.  I put up a half-wavelength (not a
typo) voltage fed inverted L for 40m as a temporary installation on my 40
foot pole, 40 feet up and 26' out "horizontally" from the tip. That was
18AWG wire and then maybe 20 more feet of light cord to a tree.  The pole
bent like a fishing rod does but I didn't have more than a few feet of sag
in the "horizontal" section.  I only had the first (bottom) section guyed.

The 60 footer is not really designed to have the same proportions as the 40
footer... the tip section of the 60 footer is thinner than the tip section
of the 40 footer.  The 60 footer is more designed to be a vertical antenna
support for the low bands.   It's overall a more flexible object under its
own weight and wind loads.

The bottom sections are big and stiff, so it would be certainly be better
than the 40 footer at a given height for supporting wire antennas... but it
tapers down aggressively at the top, I think so that it doesn't get too
topheavy for people who want to tip up a vertical.

73,
Dan
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