What I would be afraid of is the Rohn 25 top section failing after a period
of time because of the tower section twisting that will occur each time you
start the prop pitch. I have about 22 sq ft on AB105 which is 24+ inches on
a side and the starting torque and resulting tower twist is significant. I
did not realize it but I was on the tower one time and had someone in the
shack turn the antenna! I have the top set of guys 10 feet below the top
of the tower so I can tram antennas up and down.
Maybe someone can chime in and set us straight on this because I have been
turning this antenna for about 20 years.
GL N7RT
At 02:52 PM 2/5/2008 -0800, Rob Frohne wrote:
>Hi,
>
>I am having difficulty finding 100 feet of Rohn 45 or larger tower in
>the neighborhood of Walla Walla, Washington, but I can find heaps of
>Rohn 25 tower. I am considering putting a shorty 40 and a 4 element
>Steppir on top. The wind loading specs of 25G and 45G are not that
>different if you believe Rohn. The big thing is that I would like to
>use my prop pitch to turn the antennas, and I'm afraid I can't fit it.
>There are three top sections available for Rohn 25G.
>
>http://www.criticaltowers.com/ROHN%20Industries/Media/pdfs/25G/25G-11.pdf
>
>My prop pitch is the small size one I believe like those in this photo
>without the mast adapter:
>
>http://www.k7nv.com/proppitch/09a902c0.jpg
>
>Is there a way to fit this into a Rohn 25 tower so I can also remove it
>for maintenance without disassembling the tower. I do have access to a
>25AG1 section of Rohn 25 tower, but it is at 90 feet in the air, and I
>don't really feel like wrestling this thing up there and fiddling with
>it at that height just to find out if it will work when I'm sure someone
>must have already done it on the ground.
>
>Thanks & 73,
>
>Rob, KL7NA
>
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