You want to make sure that you transition to steel at the bottom anchor
points in case of a field fire as Phillystran can burn. You are also able
to move the Phill up out of easy vandalism access.
Mike W0MU
-----Original Message-----
From: towertalk-bounces@contesting.com
[mailto:towertalk-bounces@contesting.com] On Behalf Of
donovanf@starpower.net
Sent: Wednesday, February 14, 2007 11:13 AM
To: towertalk@contesting.com
Subject: Re: [TowerTalk] Guy breakup at tower...
Gary,
Phillystran cuts easily with a sharp knife, bolt cutter or hacksaw. As with
all Preforms, the thimble M U S T be the heavy duty type.
Philly is an excellent but expensive solution when you include the cost of
the two preforms, one heavy duty thimble and articulating attachment
hardware (e.g., shackles) for each guy.
The guy attachment to your rotating tower must allow articulation of the
attachment hardware. In other words, the rotational stresses must be taken
up in hardware that is intended to articulate (e.g., shackles).
You do not want the rotational forces to be taken up at the interface of the
Phillystran to end of the Preform. That will cause the Phillystran to wear,
potentially resulting in catastrophic failure.
The need to use articulating guy attachment hardware is often not considered
by hams, especially on rotating towers where these forces can be very
significant when starting and stopping rotation.
If you observe commercial tower installation practice, articulating guy
attachment hardware (e.g., shackles) is always used.
73!
Frank
W3LPL
---- Original message ----
>Date: Wed, 14 Feb 2007 10:21:11 -0700
>From: "StellarCAT" <RXDesign@ssvecnet.com>
>Subject: [TowerTalk] Guy breakup at tower...
>To: "tower" <towertalk@contesting.com>
>
>Re: my previous post on having interaction with the 6' lengths of EHS
>at the tower (through the tower it is actually ~13.5') ... it does
>interact with BOTH 10 and 15 - probably slightly more on 15 than 10.
>Frank had suggested some robust shackles and another 502 insulator...
>but I am not sure how i would then connect to the tower...
>
>
>the alternative I am considering is simply replacing this 6'
>piece with phillystran. I was looking at the 11200 which is
>0.44" thick and rated at 11200#.
>
>how does one cut this stuff?
>
>If i go this way am I simply looking at 2 preforms and the one
>6' length? Nothing else?
>
>Does one use a standard metal galvanized thimble for this (at
>the tower) - no concerns about it "wearing" over time as the
>metal galvanization is often pretty rough.
>
>the down side of this method is it requires a separate temporary
>guy line to be run vs. Frank's idea would be doable by simply
>adding another (temporary) preform just past the insulator
>preform and then using a come-along to this point to temporarily
>take the pressure allowing the new insulator shackles to be
>installed... in reality this may not be so easy either.
>
>Hindsight says I should have listened to the call for using
>Philly or Fiber. I wanted something that would not stretch and
>K7NV's notebook shows philly to stretch way too much... not sure
>where the descrepancy is between the analysis and real life but
>many have used philly with no problems...
>
>
>g.
>
>
>
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>
>
>
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