I trammed a TH-11DX to the top of my 100 foot Rohn 25 tower last
year. I did this alone with no help and found it relatively
painless. I would have appreciated some help pulling the rope! I
STRONGLY suggest you have a crew on hand. I would have, had it been
practical.
I used 3/16" 7x19 wire rope for the tram line, 1/2" nylon rope for
the pull line.
I used a rather overly complex "sling" with turnbuckles to make
levelling the antenna on the tram line easier. I had minimal
clearances and needed the boom to stay level (elements were tilted
as necessary to ensure they didn't try to slip below the top guys on
the way up).
I also used a "tiller" attached to the boom for the pull line to
help keep the antenna straight going up.
I was concerned about bending my aluminum (I know, I know !!) mast,
so I put a backstay on it exactly 180 degrees opposite the tram
line. I had no problems.
I don't have that book, but assume (hope) all of the above is
covered in it.
I haven't gotten around to putting pictures on my web site. I don't
claim my tram system was the best engineered or the safest, but it
worked for me.
I tried sliding antennas up dual ropes or cables in the past. Didn't
like it but I guess it works for some. I will only be using tram
systems from now on.
By the way, my TH-11DX manual said to put those phasing tubes on the
top of the boom...
73,
Paul N1BUG
On 06/16/2016 10:51 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.
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.
So, I'm open to suggestion and the wisdom of the group's experience.
Thanks in advance.
Dave, W8QW
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