On 1/18/01 10:15, K7LXC@aol.com at K7LXC@aol.com wrote:
>In a message dated 1/18/01 6:51:47 AM Pacific Standard Time, aa4lr@arrl.net
>writes:
>
>> 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.
>
> Huh? How do you figure that?
No one has their guys or brackets placed EXACTLY as shown in the catalog.
Each installation has to be adapted to the environment it's placed in.
>> I think it is good to exercise extreme caution when you run off the
>> tables in the catalog -- using a PE seems cautious enough.
>
> When "you run off the tables in the catalog" you're doing something the
>manufacturer does not recommend.
Not necessarily. You may be doing something the manufacturer doesn't
recommend, or it may be something the manufacturer simply didn't
calculate.
> You will be violating the LXC Prime
>Directive of "DOing what the manufacturer says" and your results are
>virtually guaranteed to fail.
If you pay a PE $300 to do all the calcs for you, and he says it's safe,
isn't that a guarantee it will work?
Part of the problem here is that hams usually go WAY BEYOND the specs
listed by the manufacturer, and get lucky enough that nothing bad
happens. But they are accidents waiting to happen. That's where the LXC
prime directive comes from.
But being off the tables may mean that dragons lurk there, but that
doesn't mean that one is going to eat you. If you hire an expert to
compute good numbers, you'd be safe from the dragons.
If you don't hire an expert, then you better be lucky....
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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