Rob -
I've successfully used the flat top sections for over 30 years with various
antenna/mast combinations. I'm currently using a 45AG4 on my 120ft tower to
turn a Force 12 Magnum 240N 40-meter beam. The openings in the top of the
45AG4 are perfect for installing a couple of rotator plates, thrust
bearings, and rotator. Finally, the big flat plate top is easy to stand on.
Looking at a picture of the 45AG2, you should be sure your rotator will fit
through the Z bracing. Also, it seems that if that long mast sleeve isn't
perfectly aligned, you're guaranteed to have a mast that is out of alignment
and cause serious problems for your rotator. Finally, once installed, your
antenna and particularly any truss system above it are going to be out of
reach, since there's no way to stand on a 45AG2.
I guess you can tell I don't like the 45AG2 design, HI.
73, Bob - W3YY
-----Original Message-----
From: towertalk-bounces@contesting.com
[mailto:towertalk-bounces@contesting.com] On Behalf Of Rob Frohne
Sent: Wednesday, April 16, 2008 1:48 AM
To: towertalk@contesting.com
Subject: [TowerTalk] Which Rohn 45 Top Section is Best?
Hi Gentlemen:
I have to choose a top section for my Rohn 45 installation, for a quad being
turned by a prop pitch. The 45AG4 (with the flat top) looks not as beefy as
the other one (45AG2 I think) to me because the Z bracing extends up to the
place where the taper begins on the 45AG2 and the
45AG4 doesn't have any diagonal bracing for about three feet, but I'd like
some other opinions. I kind of wonder if Rohn improved the top sections
along the way. Before I compared them side by side I thought I preferred
the 45AG4 because of the flat plate on top, but now I'm leaning the other
way. I have found flat tops are easier on the feet to stand on than the
tapered sections. I also noted that Rohn sells a flat top plate to put on a
regular section, but I'm still one section short and that would make me two
sections short and two top sections to spare.
Here are some photos of the two sections in question:
http://www.texastowers.com/45gtop.htm
http://people.wallawalla.edu/~Rob.Frohne/Tower/
What other considerations are there in this choice that I'm missing?
Thanks & 73,
Rob, KL7NA
--
Rob Frohne <frohro@wallawalla.edu>
Walla Walla University
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