>From my limited experience on guyed Rohn 25 (170 feet of it), there was little
>movement. I would speculate the tower did not move outside of a one foot
>circle. It might have been less because there is no point of reference when
>you're up over 100 feet on a steel stick.
Here's an idea... Rohn 45 retails for $200 per 10 ft section, so the entry cost
for your solution is greater than $2,000. Rohn 25 is less, Rohn 65 is more.
If you are serious about this, put your money in the bank and hire a crane
service when necessary to do antenna work. How many times do you need to
service the antenna each year? Then take your wife out to dinner with the extra
cash.
If that is not acceptable, forget about using a tower. Why do you need a tower?
You're still gonna use the tree for mounting the antenna, right? The problem
you face is climbing the tree. So you need a solution for climbing the tree,
not adding another maintenance item (tower).
I would go to Menards, Lowes, Home Depot, (whatever) and buy aluminum or
fiberglass ladders. A 10 ft section of ladder will be a lot less than $200.
Then I would fabricate standoffs that attach or lag into the tree. Next, attach
to each ladder section. You don't have to worry about sway or anything else.
I would use stainless hardware. If you wanted to be "extra fancy", I would make
the bottom 10 ft section removable to discourage any kid from gaining access.
Attach it when you need it.
If you bond aluminum ladder sections together, you could lay down some radials
and load it on 160m as well.
73 de Bob - KØRC in MN
------------------------------
Message: 5
Date: Tue, 8 May 2007 00:56:16 -0400
From: "Roger (K8RI)" <K8RI-on-TowerTalk@tm.net>
Subject: Re: [TowerTalk] Horizontal tower movement at the top
To: "W7CE" <w7ce@curtiss.net>, <towertalk@contesting.com>
Message-ID: <000801c7912d$36052090$6400a8c0@shop32>
Content-Type: text/plain; format=flowed; charset="iso-8859-1";
reply-type=original
> No joke! It was a serious question and I was hoping for some serious
> answers. Specifically, how much movement is normal for the top of a 100'
> Rohn 25G tower.
I don't know what would be normal, but mine is 97' with
http://www.rogerhalstead.com/ham_files/Tower29.htm on top. The 144 and 440
antennas are 30 feet above the top of the tower. I've been up there in the
same location you see in the photo, when the winds were gusting close to 30
MPH. I couldn't feel the tower move. OTOH being "up there" with 30 MPH
gusts is...interesting. Sighting through a scope I can not see it move, but
I've never checked it for movement with a transit.I'd guess it moves less
than an inch even with winds considerably higher than that.
Roger (K8RI)
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