[TowerTalk] Strength of installation raising cable for the LM470?

[Jim Thomson]

Date: Sat, 27 Aug 2016 19:26:47 -0400
From: "Roger (K8RI) on TT" <K8RI-on-TowerTalk at tm.net>
To: "towertalk at contesting.com" <towertalk at contesting.com>
Subject: [TowerTalk] Strength of installation raising cable for the
LM470?

When installing the LM470 using the raising fixture, the retracted tower 
is raised from horizontal to vertical.  The cable attaches to the tower 
roughly half way out presenting one whale of an initial load on the 
cable and winch.
K8RI

##  On the UST towers, the cable attaches to the tower, ALMOST to the TOP of
the very bottom section.  Galvanized .25 inch  winch cable is rated for 5700 bs.
.25 inch SS  cable is rated at one helluva lot less.   .25 inch galvanized aircraft cable
is rated at 7000 lbs  bs.  Although galvanized winch cable  looks identical to aircraft
cable, the BS ratings are vastly different.   .3125  or  .375 aircraft cable is even stronger
of course.   2-4  pulleys will take the stress off of any cable used.

##  UST welds a small rectangular steel plate to one tower leg, with a hole in it. Welded
on all 4 x sides.  IMO,  it would be nuts to terminate the cable only  1/2 way  along the
bottom section.   You might want to re think what they have done,  esp if laying the
tower over, with a mast, rotor,  ant on top. 

Jim   VE7RF