Most of what you need to know is at
http://phillystran.com/product-catalog/HPTG-I-High-Performance-Commercial-Broadcast-Tower-Antenna-Guy-Lines
and
http://phillystran.com/Resource_/PageResource/165.pdf
To answer your question specifically, the nominal elastic modulus
(stress/strain) is 14E6 for the 4000 to 35000# rated Philly. I'm pretty
sure that "nominal" (also called "effective") means that the compression
and elongation with tension of the stranded Kevlar fiber core is in that
value, since the raw Kevlar fiber modulus is higher (16.3E6).
it is recommended to pretension Philly guys initially at 15% of breaking
strength and they will relax to close to 10% in about a day. At a
tension of around 60% of breaking strength, Philly as well as EHS, will
take a small permanent stretch (1 - 2%). Most smaller tower guys use
the HPTG6700i which is equivalent to 1/4" EHS. I think it is commonly
believed that EHS stretches a lot less than Philly, but several
references put the "effective" modulus at 0.4 to 0.7 of the actual steel
cross section for a twisted cable. That makes the difference more in the
25% range although I have not been able to find specific data for 1x7
EHS. Most references state that you have to test the actual cable to
determine the effective modulus.
You must use guy grips made for Philly and install them properly. Wire
rope saddle clamps are not to be used for any size but the 1200 Philly,
which I won't use because guy grips aren't made for that size.
There is a huge amount of information about towers and guying also at
http://w4zt.com/n1lo/towers1.txt
Grant KZ1W
10/20/2015 10:09 AM, GMuller885--- via TowerTalk wrote:
Folks:
I have a Mosley MP-33 with WARC (10-12-15-17-20). I have added a Mosley
40 to it. Mosley sent tar rope for the guy and stays. I want to replace it
with Phillystrand. What I need to know is what is the stretch factor of
Phillystrand? Can any one help wit this. Please respond.
Gerald Muller K9GEM
GMuller885@aol.com
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