I have also seen HDBX towers CRASH with nothing more that a TH6DXX on it.
For what its worth, there is a beautiful full color photo in the new Rohn
$20 catalog showing what appears to be a TH11 mounted on the top of a BX
tower! There are no words to go with the photo and they make no
reference to it anywhere in the catalog that I have found. What does all
of this mean? "A picture is worth a thousand words?" Personally, I
think it means that Rohn is not paying attention to details and this
shows an obvious conflict with the written advice they give about using a
maximum boom length of 10 feet. No mention of element length also shows
Rohn is not paying attention to what they are saying. So does mean you
can mount a 40 meter "boomless quad" safely on a BX tower? (Hey, no boom
at all! Must be OK, right? Sure . . . ) I have grown to expect
meaningless answers from Rohn whose main concern is covering their own
butt to try to avoid liability lawsuits. Somewhere down the list . . .
way down the list . . . is providing customers with useful information
about installing their towers safely. (Hey, maybe that is not even ON
the list.)
I asked (offciallly as a Rohn Dealer) why Rohn uses fine thread plated
bolts on 25G instead of hot dip galvanized coarse thread bolts like on
the 45G and larger towers. As you have noticed, the 25G plated bolts
seem to rust a lot quicker than 45G bolts do. Also, you may be aware
that I supply Rohn bolt kits for people who want them. I was wondering
if I could actually supply BETTER bolts than Rohn does for 25G. I got a
really weasel-worded answer. Was I surprised? HA . . . not at all
surprised. After all, this is Rohn talking. The answer went something
like this:
The 25G is a 30 year old tower design and we don't remember why fine
thread bolts were specified. Maybe it was to keep them from falling
out. To be safe, you should use only what Rohn specifies.
Those were not the exact words but I have definitely captured the essence
of it. My conclusion is that Rohn will not help me to help my customers
since it violates their prime objective to keep their butt well covered.
They DID say the bolts were grade 5 . . .
With that piece of info, I intend to search for some coarse thread bolts
that are grade 5 and hot dip galvanized to provide with the Rohn
look-alike towers I will be selling the near future. Incidentally, I
don't think you can get fine threaded bolts that are hot dip galvanized
since the galvanizing will fill the fine threads too full and the nuts
won't go on like they should.
If I am successful in finding what I believe are better bolts, I will
offer them as kits like I now offer Rohn bolt kits on my web site at
<www.reprise.com> Keep checking there for new developments in
sidemounts, bolt kits, and look-alike tower sections.
I normally subscribe to Steve's advice about doing what the manufacturer
says but how can you when their advice seems to conflict with itself and
they refuse to explain stuff so you can understand it? I guess if I
become a manufacturer, then, suddenly, I will be bestowed with some
fantastic wisdom and you can all safely do as I tell you, right? Right!
There is simply NO SUBSTITUTE for having a knowledgeable PE looking over
your shoulder when you are designing a tower installation. You have to
either trust your own judgement or find and hire someone you DO trust.
Yes, it is expensive. Good, expensive advice is often cheaper than going
ahead without good advice. Only you know if you can keep yourself out of
trouble . . . And if you don't know, you probably can't . . .
Enough of my ranting.
Stan w7ni@teleport.com
n4kg@juno.com wrote:
> The 10 ft boom spec is rather arbitrary. For instance, they
> make no reference to element length, i.e. 20M vs. 2M !
>
> The REAL consideration is rotational torque. The C3 is a
> pretty light antenna with only a 10M director out in front.
> Having seen TH6's on 24 ft booms survive for years on
> HDBX towers, I suspect there would be no problem with a C3.
>
> de Tom N4KG
>
> On Thu, 04 Nov 1999 20:46:04 -0600 Jim <kg9cc@inw.net> writes:
> >
> > I know putting a C3 on this tower is exceeding the mfgr specs but
> > was
> > wondering if anyone has this combination and if so how it has
> > survived?
> > Wind speeds and the like?
> > Thanks
> > Jim KG9CC
> >
> >
> > --
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> >
>
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FAQ on WWW: http://www.contesting.com/towertalkfaq.html
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