With this new engineering obstacle in your path, you need to start looking at
heavy duty towers, as suggested in other parts of this thread. Having to
provide a design with 1/2" of radial ice loading to the city puts your
installation into a commercial grade tower. Not only does the ice add surface
area, it adds incredible weight to a structure as well.
For reference, the Heights Tower Company lists a standard 32 foot tower capable
of supporting 8 sq ft of antenna in 100 mph winds with 1/2" radial ice. You
will find it listed near the bottom of this page (scroll way down the page,
right above the picture of the 92 foot tower rated for 150 mph winds that was
installed in south Florida):
Under that photo is this statement: "Heights Towers can provide engineering
calculations and diagrams signed by a Professional Engineer licensed in your
state for $350 on standard tower configurations." Few, if any, amateur tower
manufacturers provide this type of engineering help.
If I remember correct, you have HOA approval for a 70 foot tower. I would call
Drake at Heights Tower and talk to him about your new requirements and which
Heights products could satisfy the specs. He says they can provide a "PE stamp"
to satisfy the city even on custom configurations. Heights also manufacturers
crankup towers, although they are lattice, not tubular.
Also, don't confuse the Heights design with the popular Universal towers. There
is no comparison in capacity or workmanship. I have installed and worked on
both types. The Heights sections join together with couplers. The legs are not
nested. On the larger sections, they join together with flanges, like the Pyrod
commercial products. Gary Meyer, KCØSB, had an 88' self supporting Heights when
he lived in Forest Lake.
The only "good" I see out of this ordeal is you can send the neighbors to the
"Commissioner" if any of them complain about the esthetics.
73 de Bob - KØRC in MN
Date: Tue, 12 Sep 2006 16:12:06 EDT
Subject: Re: [TowerTalk] US Tower MA 550 Windloading - 90MPH?
To: email@example.com, firstname.lastname@example.org, email@example.com
Content-Type: text/plain; charset="US-ASCII"
In a message dated 9/12/2006 1:00:12 PM Central Standard Time,
I think you've hit the nail on the head. Local authorities are
imposing "commercial grade" kinds of requirements for the permitting
(if only because it's easy, not to mention, it's legally defensible
in a PRB-1 environment), so you need "commercial grade" stuff. Tall
light posts and free standing cell towers have no problems, but are pricey.
This, to my mind, is a far more insidious trend than the HOA CCR
problem. Pretty soon, the only hams who will be able to experiment
with towers will be the ones who own acres of farm land in a lightly
Jim and all;
I think you are right. I thought the hard part would be getting an exemption
form our CCRs. I was able to do that with not a big problem. But I spent 30
minutes with the City Building Commission here in Plymouth, Minnesota and he
insisted on 90 MPH Wind Loading, 1/2 radial ice, with the antenna fully
extended (i.e. not nested). He would not move off this position no matter what
said. I tried all kind of arguments like precedent installations, aesthetics,
etc. but he would not have any of it.
Not sure what my next move is.
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