This reminds me...
One can relieve a lot of sideways forces on the top of the mast when
tramming up a large, heavy antenna. The trick is for the
tram line run from the ground up to the attachment point at the top of the
tower, and then continue down the opposite side of the
tower to an anchoring point on the ground. The continuation acts as a back-guy
on the mast. The back guy can be a separate piece
of material... but best if attaches to the same point on the mast. If you use
two separate lines, try to tension them equally.
Keep the two anchor points and the mast in the same vertical plane so as to
limit the attempt by misaligned downward force to pull
the mast out of column.
-- Eric K3NA
[mailto:firstname.lastname@example.org]On Behalf Of Tower (K8RI)
Sent: 2004 August 17 16:32
To: Jim Idelson; TowerTalk Post
Subject: Re: [TowerTalk] Tramming
My preference would be one of the Kevlar based cables which is what I use
for guy lines.
Although much easier to handle and store, lighter weight, and though they
are much easier to damage then EHS. That means the tram needs to have good,
smooth pulleys, and no sharp edges. The ends also need to be sealed from
moisture. Due to their light weight and strength they have very little
catenary. This really shows when you run a tram up one carrying a heavy
weight as there will be a pronounced dip at the tram the size of which
depends on the weight and cable tension.
Even taking all that into consideration, I still prefer the Kevlar cables.
Roger Halstead (K8RI, EN73 & ARRL Life Member)
N833R, World's Oldest Debonair (S# CD-2)
See: http://www.mscomputer.com for "Self Supporting Towers", "Wireless Weather
Stations", and lot's more. Call Toll Free, 1-800-333-9041 with any questions
and ask for Sherman, W2FLA.
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