OK, my 02 cents worth.
>I knew someone would have to be offended.... my apologies as an offense was
>not intended. Funny that you felt "comfortable" with
> Bill's statement about "cheaping out" when it was directed at those
> installing EHS!
EHS is cheaper (less expensive) than Phillystran, but I don't think by much.
>
> My point - again - is that MECHANICALLY - steel is superior to Philly. I
> cannot and did not comment about poly as I do not know
In some aspects steel is superior and Philly in others.
> anything about its stretch. The FACT is that philly DOES stretch much more
> than steel. As simple as that. So I, emphasis on I, I
The stretch is considerably more than steeland it is still insignificant.
And extra 5% initial tension will relax to the recomended 10%, or you can
retension. In aproximately 135 feet for the length of the top set of guys
on a 97' tower it is very small. My tower is heavily loaded and following
the older directions I retensioned after about a week. I haven't had to
redo them yet.
The catenary is virtually non existent where EHS will have a relatively deep
catenary. The Kevlar will have a much higher natural frequency of
oscillation. I don't know if that is good, bad, or makes no difference. The
Kevlar has almost no give from the catenary while EHS does.
Phyllistran has one characteristic I do not like. That is the Kevlar core is
very sensitive to moisture.
I sealed the end caps with Silastic RTV (TM), but I still check them
periodically and have a package of new ones just-in-case. I've had concerns
about lightning, but so far they have proved unfounded. The tower has been
struck at least 9 times now that I know of and probably more.
I'd disagree with the statement that it is easily cut. I thought it would
be, but when I started working with the stuff, I gave up trying to use a
sharp knife and box cutter. I went back to my heavy duty cable cutters.
OTOH relatively speaking it is much easier to cut than EHS but it'll take
much more than a casual swipe with a box cutter to sever it.
I do agree that Phyllistran does not have the time in the field for extended
life testing but I believe it has been around about 30 years or so.
> decided to take this variable to the maximum safety factor and to
> compromise on the other factors. Obviously you and others
> compromised in a different manner and that is perfectly fine - your
> decision - only do not (as Bill did) lessen our decision if we
> decide to go with Steel with insulators. It is not simply $'s that this
> decision is made on.
>
My old 90' tower had EHS with insulators. I pitched the whole works to go
with the Kevlar (Phillystran) when I installed the new tower. Everything
below 10' AGL is steel.
I chose Phillystran for a number of reasons. One was weight as I was doing
almost all the work myself/alone. Another was; I like the idea of no
noticeable catenary (any line with a horizontal component has a catenary)
which would remove the natural low frequency resonance, and more important
than any thing else, I would be hanging multiple HF (Half wave center fed
slopers)antennas off the tower
> Based on your description (but not knowing what poly does) I would have
> probably considered elsewise... but I am not going with
> verticals and the like.
>
>
> [PS: the guys/insulators are using preforms so no "maintenance" as you
> suggest is needed - at least not that I am aware of.]
Roger Halstead (K8RI and ARRL 40 year Life Member)
N833R - World's oldest Debonair CD-2
www.rogerhalstead.com
>
> Again - my apologies.
>
> g.
>
>
> ----- Original Message -----
> From: Phil Camera
> To: StellarCAT
> Cc: towertalk@contesting.com
> Sent: Thursday, September 22, 2005 11:33 AM
> Subject: Re: [TowerTalk] fiberglass guys...
>
>
> in my opinion it is "cheaping out" that has people going to non-steel.
> It is the desire to save TIME
> on cutting and installing insulators on the EHS steel cable and instead
> going to
> inferior guying (inferior due to stretch and ease of cutting) to save
> this time.
>
>
> I'm sorry but excuse me. Installing insulators on EHS is more
> troublesome and do all you with those peridically inspect the clamps on
> either side of the insulator? To do this you'd have to drop the guy and
> physically inspect and/or retighten these clamps every so many years or
> so.
>
> My Fiberglass Polygon guys cost much more than EHS but also less than
> Phillystran and work just fine. I installed 15 ft of EHS at the bottoms
> for physical protection and my dog will make sure no one starts climbing
> the tower with a hacksaw.
>
> Personally, my guyed tower is right next to my four square and one set of
> guys actually traverses through a corner of the four square area. I
> wasn't about to install any kind of metal, regardless of length and
> resonance, in the four square. And, I have no clamps as I used Preformed
> Products grips. My installation is top notch and no money was spared to
> do it the right way (everything designed to meet or exceed the Rohn specs
> for 130 mph design, 120 ft Rohn 45) and it's got fiberglass guys.
> Definitely not cheap charlied. Bad statement to make sir. Phil KB9CRY
> _______________________________________________
>
> See: http://www.mscomputer.com for "Self Supporting Towers", "Wireless
> Weather Stations", and lot's more. Call Toll Free, 1-800-333-9041 with
> any questions and ask for Sherman, W2FLA.
>
> _______________________________________________
> TowerTalk mailing list
> TowerTalk@contesting.com
> http://lists.contesting.com/mailman/listinfo/towertalk
>
_______________________________________________
See: http://www.mscomputer.com for "Self Supporting Towers", "Wireless Weather
Stations", and lot's more. Call Toll Free, 1-800-333-9041 with any questions
and ask for Sherman, W2FLA.
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