In a message dated 12/18/03 8:45:28 PM Pacific Standard Time,
gjerning@flash.net writes:
> Nice pictures of a 2 wire tram system.
A two-wire system where the load is slid up while sitting on top of them
should more properly be called a trolley system; i.e. a trolley car that sits
on top of two tracks.
> I used a single wire tram which is easier to rig.
This is a more useful antenna raising system where the load is suspended
below the single tramline. The haul line from the ground goes through a
snatchblock (a pulley that opens on one side to accept a rope) at the bottom of
the
tower so that the groundcrew can stand away from the tower and pull
horizontally while watching the load. The rope goes up to another pulley at the
top of
the tower and then down to the ground where it attaches to the load. Another
pulley is attached to the tramline, load, and haul rope. When you've got
sufficient tension on the tramline, then the groundcrew can start pulling the
haul
line and raising the antenna.
There are a number of tricky issues that you sort of have to address by
trial and error; i.e. rigging the antenna, using as compact of a knot and
rigging as possible, where to attach the pulley to the mast, how much tension
to
use, etc. It's one of those things that takes 2 hours to rig and then 10
minutes
to do the job. I use it about 90% of the time when installing antennas
manually.
Cheers,
Steve K7LXC
TOWER TECH -
Professional tower services for commercial and amateur
888-833-3104
_______________________________________________
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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