[TowerTalk] fiberglass guys...

[K8RI on Tower talk]

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 at 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
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