I am putting up a Rohn HDBX 48 foot tower. I will put a 3 element
SteppIR on it.
The SteppIR specs are 42 lbs, 6.1 square feet of maximum wind load,
and 16 foot boom.
The HDBX 48 antenna load specs at wind pressure of 20 psf (70.7 mph)
are loads of area = 18 square feet and thrust lbs of 360. There is a
note for all BX type towers: "Antenna types should be limited to
those having a maximum boom length of 10 feet. No engineering data
relating to the use of boom lengths in excess of 10 feet is available
and the use of such boom lengths is not recommended."
At my location, there are tall trees surrounding the tower that will
offer some wind protection, but there is no way to quantify this
I remember hearing some have located the rotator at the tower base so
that the torque is transferred to the larger tower legs. I do not
want to use a 50 foot mast, but I am considering lowering the rotor
plate for my Ham IV rotator. The rotor plate supplied is located
about 3 feet from the top of the top 8-foot section.
Would there be much advantage to lowering the rotor plate down to the
next lower 8-foot section?
Has anyone done this and have any tips on fabricating a new larger
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