re Mastrant: have experience in the smaller sizes.
Installed 5mm on two 25G towers at 65 ft 5 years ago.
I haven't needed to re-tension them, creep has been
minimal. No visible wear or degradation of the nylon
jacket. The stainless steel duplex clips have held,
no slippage, despite a couple of nasty storms that
took down a couple of nearby trees.
Based on this experience I prefer it over Phillystran.
Mastrant-M uses Dyneema, which is superior in terms
of strength and abrasion resistance versus Phillystran's
Kevlar core. Dyneema is UV resistant while Kevlar
is not. Personal preference but a big plus to me
is Mastrant-M eliminates the need for preform
grips (I don't like working with those things).
Preforms can distort Yagi patterns if installed
near the top of the tower.
Pre-stretching before installation is critical.
I used a come-along attached to my truck and a
tree then stretched each rope to about 10% of
breaking strength. This locks and engages the
lengthy Dyneema molecules. Once engaged then
in theory that greatly eliminates creep after
install. So far it's worked well in practice.
I never doubted Mastrant's strength due to the
Dyneema core. The only question I had was
longevity. So far, after 5 years, it's holding
up very well.
73 Jim K6OK
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