The recent discussion about guying for FD antennas brings up an
The design requirements for a temporary installation are very different
than for a permanent one.
Maybe it would be worthwhile to discuss what would be a practical set of
guidelines. Obviously, you don't need to design for 100 mi/hr winds,
especially if the system is failure soft, and you can just put it back
up if it falls over.
Take, for example, a 40 foot vertical made of plastic pipe and wire,
guyed with nylon rope. Not particularly durable, nor very strong, but,
if it did blow down (say, because it buckled, or because the ropes
pulled out their stakes, etc.):
a) it's lightweight, so the damage potential is low
b) it can be put back up or repaired fairly easily.
So, is it possible to come up with some reasonable "requirements"? Just
how lightweight makes it safe? What about techniques for deliberate
failure (fuse links, as it were) to control the collapse?
Yes, folks will always do things like bolt together 60 ft of Rohn25, and
"iwo jima" it up using 1/4" manilla sisal rope as guys.
But somewhere between that and the "drive AB Chance anchors and use a 80
ton crane for erection" there's probably a happy medium.
And, probably, some useful design guidelines or analysis techniques
applicable to this. There's lots of stuff out there on permanent
I've done some of this in the past looking at forces on aluminum
verticals which are guyed by lightweight rope, trying to figure out
things like, "Will it buckle as I hoist it from horizontal to vertical"
or "Will the wind load rip the roof rack off the car if I use that as a
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