Absolutely right, Steve. Not only that, but it's much much lighter, so
it's easier to handle, has less sag, etc.
One lower cost alternative to Phillystran is fiberglass rod, which I am
using as well as several other locals including W3LPL.
It's several times less expensive than equivalent strength Phillystran. It
uses special "Glas-grips" available from Preformed Line Products at
reasonable prices. The disadvantage to fiberglass over Phillystran is that
it uses bonded fibers which means it's stiff and must be shipped in a large
coil by motor freight and also must be carefully unrolled (requires 2
people) or injury may result. It's not difficult, but just requires some
attention. It also may not last as long in sunlight, since it is a
homogenous material. It is "UV resistant", but I expect maybe 20 years
down the road it may require replacement.
There are a few potential problems that both of these alternatives share.
Both of these alternative guy materials require great care to avoid
abrasions from tree limbs, etc., and should not be used within about 20
feet of the ground to avoid this and fire damage. It's especially useful
to use non-conductive segments near the tower, but you should be even more
careful not to drop anything off the tower into them as I doubt either
material, but especially fiberglass is as tough as steel in a side-load
situation. One other thing that can happen is an increase in the
likelyhood of vibration from wind because both have very smooth round
surfaces. Plastic spiral dampers can be installed - usually just one per
guy - to cure this problem at minimal cost.
The nice things about fiberglass or Phillystran are total non-conduction,
neat appearance, and light weight. In addition, as pointed out before, if
you require a lot of insulators in your situation, it can actually be
cheaper since you save the substantial cost of a lot of grips and
insulators. A typical non-conductive guy assembly will require: a shackle
at the guy bracket, 2 glas-grips, 4 HD thimbles, 2 standard EHS grips for
the length of steel guy cable within 20 feet of the ground, and a
turnbuckle, which would terminate into an equalizer plate and/or guy
anchor. Obviously, the longer and higher the guy, the more you'll save on
hardware over steel, and actually fiberglass is not THAT much more
expensive per foot than EHS steel, especially in larger sizes/strengths.
73, Tyler K3MM
K7LXC@aol.com on 04/02/97 07:03:20 PM
To: rattmann@cts.com, zettel@libby.org, towertalk@contesting.com
cc: (bcc: Tyler G Stewart/BENN/CEC)
Subject: Re: [TowerTalk] insulated guys/stacks
In a message dated 97-04-02 18:31:49 EST, rattmann@cts.com (rattmann)
writes:
> Bottom line: Within about, say, 50 feet of the tower legs I recommend
guy > wire insulators every nine feet if you are using side-mounted yagis,
alone
> or in stacks. Beyond about 50 feet out, I don't think it makes much
> difference, 28 foot lengths are probably fine, or even no insulators at
all
> are probably o.k. in those lower areas far out from the antenna (unless
you
> also have some vertical arrays in the vicinity...but that's another
matter).
>
By using a nine foot segment length, you have just exceeded the
comparitive cost of Phillystran. Use Phillystran for the first 50 feet or
so of the guys and segmented steel guys down to the ground. Lighter and
less work to boot.
73, Steve K7LXC
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