[TowerTalk] How high is safe?

[David Greer]

After being a ham for many years, a buddy of mine is ready to install his first HF beam. He bought a Cushcraft MA5B mini-beam, a rotor and a used Rohn 50-foot push-up pole.

The beam weighs 27 pounds and has 3.2 sq. ft. wind load. And last night he told me he wants to install his 6-element 2-meter quad above the MA5B. The quad is made of plastic spreaders and a wooden boom. Not much additional weight or wind load but still enough to consider. And there's the rotor too. 

So, we got into a discussion about how high he could safely extend the push-up pole. He tells me the pole has pre-dilled holes and he thinks it allows 2 foot of overlap between mast sections. I don't think 2 feet of mast overlap is sufficient for what he wants to do. (My US Tower allows 4 feet of overlap between sections.) He's not erecting a small, lightweight TV antenna which is what I figure the mast was intended for.

The mast is house bracketed 15 feet up. He was under the impression he would be able to safely extend the pole all the way up -- with guys, of course -- whereas I think he ought to plan on more overlap between telescoping sections and therefore less height -- say something like 36-40 feet.

So, how high can he safely extend the pole and will he need two sets of guys considering the house bracket at 15 feet?

73, N4KZ