[amsat-bb] Mast strength??
stargatesg1 at verizon.net
Thu Nov 22 11:13:57 PST 2007
I am installing 20' of Rohn 45 with a flat top from Normsfab
and a Yaesu GS-065 thrust bearing.
The lower end of the tower is already figured out but I'm not sure of what
strength 2" mast I need.
All this short tower will be supporting is a 3-4 element 6M homebrew beam
just above the bearing on the tower,
as well as, the elevation portion of the Yaesu G-5500 rotor with 8'
fiberglass cross mast, and M2 2MCP22, and
436CP42UG beams on each end of the cross boom.
The 2MCP22 is 2.5 sq ft wind load.
The 436CP42UG is 2.0 sq ft wind load.
I'm not sure of the WL for the rotor and 6M beam.
The mast will have to be at least 18'-20' long to give 2-3 foot inside the
tower to the AZ rotor and
enough sticking out the top to give 1/4 wavelength (at 2M) spacing between
the satellite antenna's
and the 6M beam.
The satellite antenna's are close to 20' long and mount from close to the
center so I need at least
10' (+1/4 wavelength) above the top of the 6M beam.
I'm not an engineering type so I thought I would ask on here. What
and material would the mast need to be to support this.
I am thinking T6061 aluminum, .25" thick wall, 2" outside diameter mast.
I live in a 75mph wind zone.
Any help would be much appreciated.
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A TRUE friend will be sitting next to you saying.....
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