I am at the very initial stages of planning my first tower. Here is what I
have done so far. I have read Steve’s book “Up the Tower”, and ARRL’s
“Antenna Towers for Radio Amateurs.” I then visited the zoning department
and the building permit department for my geographic area. I have also
read the CCNR’s for my neighborhood.
I would like to install a 70 foot tower in my 5-acre, heavily wooded
lot. (70 feet will put the antenna about 10 feet above the tallest trees.)
I would like to support one or more antennas on top of the tower having a
total of about 20 square foot wind-load.
There is no problem with the zoning department. The building permit
department told me I must meet Section 1609.1.1 (4.) of the 2006
International Building Code. The structure must meet TIA/EIA-222 for a
3-second gust of 130 MPH. (I am only 8 miles from the Atlantic in South
Carolina, so the area is rated for 100 MPH.)
To comply with the neighborhood CCNR the tower must be “attached” to our
2-story house. If I combine the high wind speed with the attachment
requirement, I am initially led to the Rohn 55G Bracketed tower. However,
I cannot find specifications from Rohn that meet the 130 MPH requirement.
The specs for the 55G only go up to a 3-second gust of 105 MPH.
Where do I go from here? Do I need to add guy wires to the upper
sections? If so, where do I get the specs for the guy wires? All
suggestions would be welcomed for this new comer to towers.
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