>My point is not to present a legal dissertation on negligence, but if I were
>manufacturing towers for radio amateurs when it's common knowledge
>throughout the tower industry that hams oftentimes work on their own towers,
>I would document the hell out of my product and cover every reasonable and
>rational angle. Remember, the degree of information presented doesn't have
>to be perfect, just reasonable. (See the Rohn product catalogs for an
>example of this).
You sound like a knowledgeable attorney to me. I am not. I am just a Rohn
tower dealer with a LOT of questions. I get questions all the time from my
customers who need advice on how to install their towers. More often than
not, the Rohn catalog leaves them with lots of important questions
unanswered. I KNOW Rohn is aware that these questions exist. They simply
do not address them in their catalog and I wonder if not addressing them
really puts them in a dangerous legal position . . . worse than trying to
answer them. The thought of being in the tower manufacturing business
scares Hell out of me. It's bad enough just being a dealer . . .
So what kind questions am I talking about that Rohn does not address in
their catalog? Here are a few examples.
1. Ham wants to install a guyed Rohn tower and can't put the guys exactly
120 degrees apart. In what ways and by how much must he "derate" the load
on the tower to compensate for this deviation from the pictures in the Rohn
2. Ham wants to install a guyed Rohn tower and can't put one or more of the
guys out quite as far as the diagram in the Rohn catalog says he should.
How does he "derate" the tower in this case?
3. Ham wants to install a guyed Rohn tower but he wants to stack antennas
on a mast that puts some of the load well above the "2 foot" point where all
loads are shown in the Rohn catalog diagrams. How does he compensate for that?
4. Other than the BX tower, I know of no data that suggests how much torque
a Rohn tower will safely take. How do you know if you can safely use a 60
foot long 20 meter Yagi on Rohn 25? On BX tower, they simply say you can't
use any antenna with a boom length longer than 10 feet. I am not aware that
they address boom length at all on their other models.
5. Speaking of BX tower, almost ALL installations I have seen use longer
than 10 foot booms. How does this affect the area of antenna that can be
safely installed on them? Rohn would tell you that you can't do it but
thousands of installed towers would say you can. So thousands continue to
do it, in spite of Rohn's warnings.
While on BX tower, the HDBX is supposed to take 18 square feet with a
maximum boom length of 10 feet. What kind of a ham antenna has those
specifications (other than a dish)? But Rohn lists them in their "Ham
Catalog" and several well known ham dealers advertise them in QST and other
magazines, obviously saying they are intended for ham use. What "ham use"
is consistent with the 18 square foot and 10 foot boom specifications?
I suppose you could say it should hold up a "boomless quad" for 40 since
that would probably meet the 18 square feet and less than 10 foot boom (no
boom!) criteria. I doubt it would stay up.
6. Rohn's current information regarding bracketed towers always require two
brackets. I don't know of a single tower installed that way. Rohn MUST
know that nobody installs bracketed towers according to their instructions.
So what is the proper way to install a bracketed tower with a single
bracket? How much can you put on it? I have seen lots of people guess at
this but I find no help in the current Rohn catalogs.
I could go on with other examples involving elevated guy posts, side-mounted
antennas, and many other things but there is no point in it. My point is
that the Rohn catalog information leaves A LOT of unanswered questions for
the user to guess at. Rohn's answer is to pay them big bucks for an
engineering evaluation of your specific system. I have never known any ham
to ever take advantage of that service. Who could afford it?
So when we have questions, we get on this reflector and we get some pretty
good empirical data from experienced users who have seen a few tragic
failures and have taken the time to understand the failure modes. I have
never seen Rohn help out in this area. What they must have seen over the
years could have a very devastating effect of their business, if they chose
to share the information. At the same time, it could save some lives. What
do they risk in NOT sharing failure data? Apparently nothing . . .
What you don't know can not only hurt you, it can kill you . . .
This post ought to create some lively discussion.
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