In a message dated 98-04-01 12:48:24 EST, firstname.lastname@example.org writes:
> The Rohn 25G is rated up to 40 foot self supporting depending on wind
> zone and wind loading per the Rohn catalog. The drawing for the self
> supporting base specifies rebar on 12 inch centers in a 4 x 4 x 4 base
> regardless of height or wind load. The base section must be either the
> bottom tower section or an imbedded short base section. No other type
> of base is permitted.
As far as the self-supporting parameters, the latest Rohn info shows that
it will take 1.5 sq.ft. @ 70 MPH and unrated @ 80 MPH. This is from the Rohn
"Manufacturer's Technical Information for Bracketed or Self Supporting
Towers". It's free from TOWER TECH for an SASE.
> The tower will be 35 foot high mounting only a lightning rod, omni TV
> antenna, 2M base antenna, 40M inverted V, and one end of an 80 foot
> inverted L. I calculate 1.35 sf wind load--all round section. This
> will comply with Rohn's 80 mph rating. K7XLC will be quick to point out
> that my county is a 100 mph zone--information he kindly provided me.
> However the only way those kinds of winds occur here is during the very
> (so far) infrequent hurricanes.
> I am not concerned about being under the rated wind speed for this
> county since the property I bought came with a mobile home. Should
> winds in excess of 80 mph occur, I fully expect the tower to fall on a
> vacant lot. I will definitely not be anywhere near it.
It's your installation and you're violating the LXC Prime Directive (DO
what the manufacturer says) and I would recommend installing it for safety and
long-term reliability. 30 feet of freestanding 25G is rated at 1.7 sq.ft. @ 90
MPH. That would make me feel better.
Cheers, Steve K7LXC
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