[TowerTalk] Re:Big Grips/Pre-forms (long)

[dpbunte@juno.com]

Ty-wraps, tape or hose clamps are often used to keep the ends of
pre-formed guy grips from coming un-done...but  I question their value in
the most extreme situations.  

I believe the greatest risk is that a chunk of ice may slide 50 or 60
feet down the guy wire, and when it hits the ends of the pre-form it
almost instantaneously compresses it enough to allow the guy wire to be
fully released.  After having seen this happen, a TV engineer at Sangamon
State University in Illinois (WSSR I think), invented a device which
could be clamped to the guy wire several feet above the preform.  The
device was made of lead, was conical and was installed with the point
facing up the guy wire.  That way, as ice slid down the wire, it would
shatter and be scattered away from the wire when it struck the point of
the device.  It is a two-part device which can be installed after the
guys are in place.  Different sizes were made for each common size of EHS
cable.

The engineer was named Jimmy, but I am sorry that I cannot recall his
last name...he is a ham, and may have retired by now.  

Realistically, in most environments, most ham towers are not going to be
tall enough to gather enough ice on the guys for the above risk to be
very high.  In fact, I think the devices, although fairly inexpensive,
are seldom used on towers less than 600' high.  That is just a guess
based on conversations with Jimmy some years ago.  

We have 3 - 250' towers, and one 450'  where I work, here in central
Indiana, and feel pretty safe with the basic shield, compressed over the
end of the pre-form.  That  reduces the risk of water migrating into the
end of the pre-form and causing it to loosen as the water expands during
freezing.

I knew a fellow who went out to his tower if there is a freezing rain,
and hit each guy wire with a baseball bat, causing A LOT of ice and water
to fall from the wires.  This surely removed many pounds of strain from
the system, even if there was little or no risk of a pre-form being
loosened by ice.

Sorry for the length, but thought I would add my
experience/thoughts/observations.



Dave -K9FN-


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