On 2/2/13 11:39 AM, Brian Alsop wrote:
I guess the rest of the earth is flat. With the uneven terrain around
here no way pre-cut guys would work. Also there is a likelihood that
where you try to screw in an anchor, you can't because of rocks, roots
or whatever.
Sandbags or lead shotbags are your friend. You get it close, hoist away,
then move them in or out as needed.
yeah, they drag on the surface, but it's a temporary install.
A back of the envelope shows that a 40 foot mast 2" in diameter would
have a wind loading of about 16 lb in a 30 mi/hr wind. Using my guy
anchor at half the height scheme, the "dragging force" is only about 8lb
(half the force is on the base of the antenna, half at the top),
although the lifting force is twice that. You need a pretty heavy anchor
to hold it in place, so it's gonna slide. (you need at least 24 lb to
hold, if friction coeff is one). My sandbags are about 10 lb.
To stabilize things, I've piled rocks on the sandbag, for instance. I
think a 5 gallon water jug might work well, but you need to carry water
then (or be able to fill it on site, which takes time).
And I'm not real interested in carrying 100 lb of sandbags or lead shot
around.
But in a 15 mi/hr wind, the load is about half the load at 30 mi/hr.. so
that's getting more reasonable, and to be honest, 15 mi/hr is fairly
windy. If it falls over in a Santa Ana... oh well.. it's not so heavy
that anyone will get hurt.
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