Art,
I would not go more than about 40 to 45 ft. with the fiberglass poles. Maybe
use the aluminum equivalent if you go higher than that.
The pole sections to which you refer are the 1080-01-179-6025, LCSS which are
designed to support camo netting, not for antenna installation.
These masts have safely been used for temporary installation and some folks use
them permanent there was even an article on Eham where a fellow puts them up 70
ft. That I beleive is asking for trouble. There are also several types of
these. Some have thicker wall than the others and some do not have female end
ferrules and can split.
All of these poles require guying about every 4 sections or 16 ft.
I have some info on my web page:
http://www.freewebs.com/ai4wm/mastinformation.htm
If you can find them use the MS-44 sections from the AB-155/U masts or the
sections from the newer military mast (I think they are MS-86). These are
designed to deploy antennas, but will still require guying.
The telescopic poles from MFJ, Spiderbeam, and Jackite taper and get rather
thin at the top. Wonderpole makes one that is much better than any of the
others.
73,
Bill
AI4WM
--- On Thu, 12/11/08, Art Trampler <atrampler@att.net> wrote:
> From: Art Trampler <atrampler@att.net>
> Subject: [TowerTalk] fiberglass masts
> To: "T talk" <towertalk@contesting.com>
> Date: Thursday, December 11, 2008, 11:08 AM
> This is an antenna support question...so hopefully it is
> close enough to a tower to allow a little discussion!
>
> I have been thinking about constructing an antenna support
> of military surplus 48" fiberglass masts. I would like
> to get up close to 70', though, both for an inverted vee
> and to run a wire vertical up it.
>
> Here is what I am considering: using 3 of the masts, joined
> with U-bolts around (or inside?) of 6" or 8"
> diameter PVC pipe, sliced into 3" or 4" pieces. I
> would rather use u-bolts than drill/bolt through so as not
> to weaken the fiberglass, and also to make keeping things
> even a bit easier.
>
> I would guy this at two, or if necessary three levels with
> dacron rope.
>
> So am I crazy? Or is there a real structural advantage to
> this over a single, guyed mast such as the one sold by MFJ?
>
> For the vertical, I am playing with the design for the
> relay-switched dipole that was in QST a few months ago,
> using ladder line. With such a design I could put relays
> for each band (two each on 40 and 80/75) for full coverage
> with very little, or without compromise. Perhaps I could
> later add base-loading for 160, or a combination of top
> loading/capacity hat switched in/out and something at the
> base. The fiberglass would lend itself to this, and to
> supporting an inverted vee.
>
> Feedback is appreciate, and since this isn't a true
> tower (of steel or aluminum), please feel free to contact me
> directly.
>
> Art, KØRO
> atrampler@att.net
> _______________________________________________
>
>
>
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