[TowerTalk] pipe masts

[Frank T. Brady]

I'm putting some schedule 40 pipe together with coupler/reducer fittings to
form a sturdy guy anchor/flagpole. The bottom is a 10 foot section of 3"
pipe, coupled to a 10 foot section of 2 1/2" pipe, coupled to a 10 foot
section of 2" pipe. About 4 feet of the bottom section will be imbedded in
concrete (with a threaded coupling or bolts at the bottom to 'grip' the
concrete).

Although the pipe supply place seemed to agree that this would be a sturdy
structure, I thought I'd ask the list members if you agree (this is a 50 to
70 mph 'zone' and a 3'x5' flag will fly from the top).

Also, after seeing how strong this pipe is and the coupling fittings that
are available, I realized that one could construct a fairly high steel mast
out of this stuff.  

Is it very difficult to calculate the self-supporting limits and guyed
limits of such a mast?

I realize that I would have to have a crane drop the 'mast' into the hole,
but a self supporting steel mast would sure be better than the 7 tiers of 3
guys necessary for the H70 I've got on order (IF I can assure that a pipe
mast is safe).

The load is whatever is created by pulling the slack out of a wire antenna
strung between the top of the two masts (something like 100 pounds max?).

Also, the top load will be equalized by two back-stay guys opposed to the
antenna pull.

Thanks,
 Frank T. Brady - W0ECS
 Wildomar CA



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