I don't intend to ruffle any feathers, nor do I direct this at any one
individual
but, the number of assumptions made and the knee-jerk reactions and
false statements being made in response to a suggestion that
magnetic mounts can be successfully used in some circumstances is both
amazing
and somewhat disappointing. I would have hoped that we could have a
more "professional" atmosphere on this list.
"Best practices" if it in this case is taken to mean to use a
commercially available
professionally engineered mount which has been engineered to "withstand
100 mph wind loads" (to use an arbitrary example) instead of using a
mounting
system which will withstand much more than that, albeit not a
"professionally
engineered" solution is just wrong. I would rather go with the stronger,
more stable solution rather than compromise on the integrity of the
mounting
to attain the engineer's label. Whether that is "best" or not I suppose
would
depend upon whether your goal was safety or following the "norm".
It has been suggested in another post that nothing should ever be
mounted
on a tower that some idiot might at some point decided to use as a
tie-off
anchor point. That is a good idea in practice, but how many of us have
attached
a lightweight yagi antenna to a tower leg, assuming that nobody would
ever
be foolish enough to use it to tie off to, or even use as a foothold or
handhold?
Are we supposed to only use yagi antennas engineered to withstand
improper
use in case some idiot decides to tie off to one? What about omni
antennas consisting
of a thin metal rod, possibly encased in a small fiberglass tube? The
point is
that while safety should be a top priority, the goal of never mounting
something
on a tower that could at some point be mis-used as an anchor or support
point
is an unrealistic goal, which I would go so far as to say that those who
propose
such a goal have not been able to meet themselves, assuming that they
have
actually mounted equipment on towers.
As far as mounting heavy stuff which might fall off and hurt someone, I
would
assume that the reaction(s) in this thread would indicate that
non-penetrating
roof mounts, chimmney mount brackets, clamping to roof vents not
specifically
engineered to withstand such use, and all other forms of mounting which
might
under some conditions fail and allow the "heavy" objects to fall
would be
outlawed in your town were you given the regulatory authority to do
so. Or,
perhaps because they were "designed by professionals" they would pass
muster in your book in spite of the fact that any fool looking at
them could
imagine a likely scenario in which they would fail.
I have seen numerous "professionally engineered" solutions which I
would not
use in a given circumstance because of the likelihood of it failing, and
have
in several instances used a solution designed by an "amateur" (me) so
that
I could rest easier at night, knowing that I have done what I could to
mitigate
the actual risk to life and property. Sometimes that means doing
things in a
way that is "out of the norm", which scares some people. That they are
scared
by that which is not "normal" without a rational basis for their fear is
disheartening. Many rules and regulations have been foisted upon us and
have limited the options available to those less suited for the job
at hand
simply because of those irrational fears.
I have seen mounts which were "professionally" mounted to towers using
welded studs (either welded to existing towers or in some cases to
towers
being constructed) using small diameter bolts which were definitely not
something that I would trust my life to, and other mounts that were well
engineered and would likely withstand likely wind loads on the equipment
that they were supporting, yet which will probably fail in hurricane or
tornado
force winds. Are these in-appropriate? should we engineer everything to
withstand +500mph wind loads? Should all magnets be outlawed? (I see
lots of magnetically mounted omni antennas on vehicles traveling at high
speed down public roadways, can you imagine that???) I bet some of those
responding negatively to magnetic mounts even have magnets holding stuff
on their refrigerators, one of the highest use and traffic areas in the
typical
home.
I can show numerous examples of solutions designed and built by
amateurs which in the final analysis are safer and better solutions
than
commercially available, professionally designed solutions to the same
problem, but the "amateur" solutions do not have the blessing of the
designed by professionals label. Does that make them inappropriate? In
the views of some people, sadly, the answer is yes.
All of that being said, whenever one is considering their options for
mounting
equipment on a tower, safety should be a top priority (and I would add
should
take precedence over having a "designed by professionals" label) and one
should never mount equipment in a fashion which is likely to cause
serious injury
or death to innocent members of the community.
John
Clint Ricker wrote:
Not to ruffle any feathers and not directed at anyone, but lack of
problems
on a single install does not always coincide with proper approaches on
this
sort of thing. Best practices are just that--the best approach(es) to
doing
technical work--there are also bad practices, not so good practices,
it may
work practices, it should hold practices, and we'll deal with that
later
practices. They often will get the job done, but, just so that
we're all
clear on this, none of the later category, no matter how many one-off
implementations are functional to some degree or another, will ever be
"best
practices".
Personally, if I was in your town or especially on any sort of a
planning
board or whatever, I'd be fairly nervous about the idea of big heavy
objects
being held up by magnets, especially when (seemingly) it is being
done by
people who don't necessarily have a lot of experience with calculating
load
bearing stuff with magnets. The fact that you hold up anecdotal
evidence as
a basis for its validity rather than "it's engineered to withstand
100Mph
winds or whatever pretty much illustrates my point--this is just a bad
idea. Just keep in mind that one falling antenna that kills one
person is
enough to bring out major liability lawsuits that you will not be
covered
against, not to mention bringing some fairly major legislative
regulation
and licensing requirements for mounting affecting the whole industry.
If I
knew that antennas in my area were be magnet-mounted by amateurs, I
would be
personally leading the charge for some regulation on this.
Ok, sorry for any offense. I'm not trying to flame anyone, but this
is just
not a good idea.
-Clint Ricker
Kentnis Technologies
On 7/12/07, Ray & Jean <[EMAIL PROTECTED]> wrote:
Carl
We used one from Tessco that has a collar that bolts around the
vent on
top
of tank and adjustable legs for leveling.It has been up there 4 years
with
no problems.It was easy to install approx 1hour.
Ray Hill
----- Original Message -----
From: "J. Vogel" <[EMAIL PROTECTED]>
To: "WISPA General List" <wireless@wispa.org>
Sent: Wednesday, July 11, 2007 6:12 PM
Subject: Re: [WISPA] Water Tower Mounts
> Carl Shivers wrote:
>> We are going to be mounting Panel Sector antennas to 2 Water
Towers.
One
>> tower is ideal with a rail that has been designed for pipe
mounting.
The
>> other is not so kind. It simply has a ladder up the side and
over the
>> top,
>> no catwalk. We were thinking about using one of those 170 lbs.
Water
>> Tower
>> mounts. This means we either have to get a welder up there to weld
the
>> plates or come up with an industrial epoxy solution.
> I have successfully used magnets on a couple of towers for 2 years
now...
>
> I don't completely trust them, so I also run a safety cable
around the
> mast
> and anchor it to a solid projection on the tower so that if the
magnets
> did
> turn loose, the mast wouldn't hit the ground, but in two years, and
> through
> several thunderstorms and pretty good winds, the magnets haven't
shifted
> a bit that I can see.
>
> --
>
> John Vogel - [EMAIL PROTECTED]
> http://www.vogent.net 620-754-3907
> Vogel Enterprises, LLC
> Information Services Provider serving S.E. Kansas
>
>
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