jim Jarvis wrote:
> Ignoring, for the moment, the prime directive, let's look at what
> you're doing if you guy a crankup tower.
>
> The lateral forces on the tower, which cause it to flex and shed
> load, are transferred to
> the guys, and to the vertical structure itself. With a crankup,
> that means to the hoist cable!
> The cable is not specified for anything more than lifting the weight
> of the tube, with some
> safety margin.
Except if you just guy the bottom section. I'm assuming that the lowest
tube has plenty of compression strength. I'm not sure this buys you
much (I suppose you could get away with a smaller (or almost no) base,
since it doesn't have to take the overturning moment)..
I've seen this strategy used with things like tower trailers. Solves
the problem of keeping the whole thing reasonably upright, without
adding load to the hoist cable.
Jim, W6RMK
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