Excellent info Jim!!! Here is the part where I sit back and shut up!
:-)
Dino - K6RIX
dino@k6rix.com
> -------- Original Message --------
> From: Jim Lux <jimlux@earthlink.net>
> Date: Mon, June 26, 2006 3:35 pm
>
> HOWEVER... watch the wind load issue. You may find that the 40 foot mast
> with a small beam on it has enough overturning moment in a fairly low wind
> (e.g. 60 mi/hr) that outriggers are impractically big.
>
> That 60 mi/hr and 9sq ft is a force of 82 pounds at the top of the mast.
> That results in an overturning moment of about 3500 pound ft + about 4000
> lb ft for the force on the mast itself (assuming it's 42'x6"). Let's call
> that 8000 lbft. If you've got a 10 ft outrigger, it's going to have to
> take a 800 pound load (and also implying that the trailer has to weigh 800
> pounds to hold it down, although, ballast on the upwind outrigger would help)
>
> There's some similar calculations at
> http://home.earthlink.net/~w6rmk/antenna/mastcar.htm when I was trying to
> figure out if I could use my car to hold up a 50 foot portable mast.
>
> I suppose the issue is whether you expect the setup to be "totally self
> contained" or "a convenient carrying device for the rig"
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