On 1/16/01 23:39, K7LXC@aol.com at K7LXC@aol.com wrote:
>> What it does NOT show is any ratings for bracketed towers in excess of 90
>> MPH
>> wind speed ratings. My guess is they don't recommend it.
>
> GOOD THINKING!
>
>> That's not to say that it "can't" be done...
>
> YES - that's exactly what that means - it can't be done.
I disagree, Steve. I don't think it means it cannot be done.
Instead, I think it likely means that Rohn didn't think this was a likely
installation.
I'm sure that the Rohn tower materials are capable of supporting SOME
amount of antenna structure in certain bracketed installations at 110
mph. It could be that the capability in a bracketed installation is so
limited, or they felt that such an installation was so unlikely they
decided not to include figures.
A PE could compute the exact capabilities of bracketed installations at
110 mph. And such installations would be safe.
Just because an exact installation isn't in the catalog doesn't mean it
is impossible. If that's so, almost NONE of the uses of Rohn 20, 25,
(35), 45, 55 are possible. There's only a extremely small percentage of
installations that follow the catalog installations EXACTLY. (For one,
almost NO ONE has perfectly level ground)
I think it is good to exercise extreme caution when you run off the
tables in the catalog -- using a PE seems cautious enough.
Bill Coleman, AA4LR, PP-ASEL Mail: aa4lr@arrl.net
Quote: "Not within a thousand years will man ever fly!"
-- Wilbur Wright, 1901
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