On 6/16/16 7:51 AM, Dave Leisman wrote:
I have one of these beast that I have resurrected and am ready to put on top of
a 70' Rohn 45 tower. The tower is properly guyed and
steady as a rock. My question though is how to get the antenna from the ground
to the top of the tower.
At Dayton this past spring I bought the ARRL's book on towers and antennas and have been
reading about "tramming" the antenna to the
top and then placing it accordingly. That seems attractive but this is a very
heavy antenna and my concern is the strength of the
mast to hold the rope tight while the antenna is making its way to the top.
My understanding is that in the "tramming" method the antenna is carried to the
top by a sling (more or less)and then put in place
once it reaches the top.
The other method involves sliding the antenna up two ropes spaced apart at the
bottom of the tower, beyond the guys wires. This
sounds good but there are phasing tubes on the underside of the TH_11 that
could be (most likely would be) damaged in this method.
With lots of help to manage tag lines, you can probably do this without
breaking things. Can you flip it over and put the phasing tubes on the top?
You'll need a bunch of people: 1 on the haul line pulling it up, and 2
helpers to stabilize the antenna as it starts up the slider lines and to
handle the tag lines and keep the antenna oriented properly.
Then you'll need whoever is going to do the work on the tower itself.
I've thought abut paying a guy to bring in his crane (lots of height and
lifting capacity), but that's another cost that I'd like to
avoid if at all possible.
Rather than a crane, think about renting an 85 foot bucket truck.. You
can strap the antenna to the side of the bucket, and it gives you a
place to stand while you work on it.
General comment:
All these "sliding/tramming/haul aloft" schemes are really for people
who have lots of skilled labor around and no access or funds for "power
tools" like bucket trucks.. If you have a crew used to setting sails on
a square sailed multimasted ship, then these "yo ho, haul, me hearties"
schemes work pretty well.
My experience with untrained crews with strong backs is that it tends to
be a bit more chaotic and, shall we say, exciting.
If you have a crew of riggers used to building and setting theatrical
trusses and the like: it's smooth, they know what they're doing, they're
used to managing hanging loads by pulling just right on a rope.
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