I'm not an expert at it, but I've got some suggestions for things I know
work well.
First off, use steel aircraft cable...at least 3/16"...for the tram. It
must be tensioned fairly tight to minimize sag under load. To support the
antenna, we had best success hanging it from the tram line from a pulley
with a closed hook that attached to a good come-along, which was attached
toa webbingsling around the CG of the boom. I think I'd add a rope loop
throught the come-along just in case it failed. Any decent rope is then
attached hook near the pulley or to the boom itself, run through a block
near the tram attach point on the tower, then down the tower to another
block, and then out away from the tower. Use a small lawn tractor, or
several strong men to pull the rope slowly.
I've found it's best to haul the antenna up in the attitude and position it
will take once attached to the tower. So the boom is horizontal to the
ground. Using a couple of small ropes tied in the middle of the boom, then
wrapped around ends of the boom and around the "outside" ends of the
reflector and last director, you can easily control the position of the
yagi as it is hauled up. You must be careful with these ropes not to
damage the elements. Once the beam is up against the tower or mast, you
can just let out the come along to drop the antenna into position and clamp
it onto the mast or ring rotator. The tag ropes just get untied in the
middle and they should easily slip off the antenna boom and element.
Make sure that everything is set up so that no one has to stand directly
under the beam as it passes up the tram. There probably shouldnt be anyone
on the tower, either...at least til it's up and ready to be lowered into
position.
73, Ty K3MM
k0wa@southwind.net on 09/02/97 09:55:45 AM
To: towertalk@contesting.com
cc: (bcc: Tyler G Stewart/BENN/CEC)
Subject: [TowerTalk] Tram Questions and Observations
This weekend, K0TQ and AB0S spent a whole lot of time (6 hours) on K0WA's
tower replacing the top section, mast, rotor, etc. They put up heavier
stuff in preparation for a larger antenna. I want to thank them publicly.
Although the larger antenna was not ready to ascent to new heights we did
put up a TA-33 until the other antenna (TH-6DXX) is rebuild and ready.
To raise and lower the antenna, we used the tram system described on the
reflector earlier this year. My observations are as follows....
===>Do not use nylon rope. It streaches way to much. Should be a help
rope
like a climing robe that will not streach.
===>The sling has to be made just right or problems will occure.
===>A "tiller" needs to be installed to keep the antenna parallel to the
tram line....but...what is the best way to do that?
===>The tram line rope needs to be tied at least 2 to e times higher than
the sling height above the boom.
Here are some of my questions.....
Do you use a come-along to tension the tram line?
Do you use 1/8" aircraft cable for the tram line so there is no flex?
How do people make the sling on the boom? We used norman hemp, tied in the
middle and balanced. Do people you cable that is semi-perminantly
installed?
How long is the tiller and does it lead or follow the boom? Does it have
its own pully...or do you use a carabiner? How tight is the tiller
attached
to the tram rope/wire...in other words...do you use a rope to attach the
tiller to the tram line or do you use something rigid?
Comments from the experts are needed. The TH6 is waiting and the bands are
getting pretty good.
Thanks people....
Lee Buller
k0wa@southwind.net
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