[TowerTalk] tramming vs. "riding the rope"
Randall K Martin
rkmassoc at comcast.net
Wed Sep 9 13:28:42 PDT 2009
I am one of those that would say tramming is easier. Way back with my
first tower, I did the two rope method to raise a 4 element cushcraft
20M to the top of a 70 foot tower and it was a real pain. Over the
years, I've refined my methods.
I've done quite a bit of work here this summer and have trammed at least
a dozen antennas up and down the towers, the largest ones being KT36XA's
and an old KLM 15 meter monbander on a 36 ft x 3 inch boom. I have been
able to successfully handle all of these with no help whatsoever, except
that I did need help from my son for about 10 minutes handling a tag
line on the KT36XA that went up to the 90 foot level. I have clearance
problems with one guy wire and needed someone on the ground to help get
the antenna up and over that one guy. My tram line is 1/4 inch diameter
aircraft control cable. Most of the time, I use a lawn tractor to
carefully pull the larger antennas up the tram line. If the tram line
angle isn't too steep, it is pretty easy to pull even a KT36XA up
without any help.
I never attach the tram more than three feet up the mast, and usually
less than that. For the heavier antennas, I run the tram line up and
over a heavy duty pulley attached to the mast and down to the opposite
side of the tower. That way, I have a backstay and there is very little
horizontal stress on the mast. When the antenna gets to the tower, it
ends up a few feet below the top of the tower. All I do is release the
tension on the tram line at that point, climb the tower, attach a come
along to the antenna, and ratchet the thing up the rest of the way.
This has all been discussed in previous threads.
To prevent "turtling" of the antenna, I fabricated a couple quick and
dirty brackets made out of a 3 inch u-bolt, a piece of angle iron, and
an eight inch long piece of 1-1/4 inch square aluminum. The u-bolt
attaches to the angle iron, and the aluminum sticks out from the angle
iron. I drilled small holes through the other end of the aluminum.
Once I have the antenna balanced with my slings, I simply mount these
brackets on the boom a few inches inside the sling attachment, with the
aluminum pieces pointing straight up, where the tops of the aluminum
extend just past the sling. I then run some 12 gauge copper wire
through the holes in the aluminum and around the sling. This keeps even
the top-heavy KLM yagis from turning over. You could probably use steel
for both parts of the bracket and then attach your sling directly to the
top end of each bracket but I just happened to have the aluminum on
hand. If you want, I can send you a photo of one of the brackets.
Finally, what I think is the most important point is to use a tiller
bar. Lots of info on that in past threads, but all it is is a short 2-3
foot long piece of angle iron with mounting holes for a 3 inch u-bolt at
one end and a hole for a carribiner at the other end. The tiller
attaches at the center of the boom and the pull rope attaches to the
tiller. By adjusting the angle of attack with the tiller, you can
closely control the attitude at which the antenna approaches the tower.
The tiller also keeps the antenna from rotating sideways. I found this
was the key ingredient to being able to tram large antennas very easily.
Sounds like the rope method works fine for you on the small antennas,
but I wouldn't give up on the tramming method for raising that 80M dipole.
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