With due respect, I think it is necessary to make a fundamental
Observation on this topic.
Rohn's catalog...and mine is missing so I can't verify the numbers...
But as I recall, it specified a 2 sq. ft. windload 30' above a house
bracket, for 25G. That's considerably less than a 3 el tribander will
present.
N4ZKF, Dave, has 40' 25g housebracketed @ 10'. Windloads are more like 12
sq ft, 30' above the bracket, and he reports surviving some harsh weather.
I had 60' of 45G, house bracketed at 6' & 16'...with an lpda and vertical on
top. It survived some harsh weather.
Neither of those are relevant.
What IS relevant, is that the structure is not RATED for what's proposed.
If the tower fell and nothing would be hit, then the risk is low...and who
cares? But if it would hit a populated house? I would not personally risk
an installation which would make you liable for serious results.
It IS true that Rohn's specs were highly conservative, and were influenced
by anticipated litigation. Hams have been overloading the stuff and getting
away with it for years. But risking life and limb for the sake of a hobby,
or a few dollars...does that make sense? Doesn't to me.
Having said that....I personally believe that 25g is stronger than hbdx, and
with a proper foundation, would serve reasonably in the 40-50' vicinity.
Just don't ask me to climb it. I've built 100+' 25g...and being 30' above a
guy is a puckering experience. It's THAT flexible.
Jim/N2EA
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