Norm,
Based upon N5RP's anecdotal account of running 65' of 45G without
guys thru two hurricanes, you are probably quite correct. His installation
survived the equivalent of 3 times the manufacturers rated wind load.
I think Joe, is probably being overly conservative with regards to 20' of
45G and a small (5sq ft) tribander. This would probably meet Rohn
specs, even under 110 MPH conditions.
The only problem I see with second guessing Rohn, is you don't know how
much of the spec margin is for the lawyers, and how much is for process
variation and aging. The actual breaking strength of the tower will vary from
section to section and with age. Perhaps Bob was lucky enough to have
some above average sections, others might not be so lucky. Also. don't forget
that Rohn is also under competitive pressure not to underate their product too
much. Pretty hard to second guess all this in a vacuum.
Myself I will stick to the specs. I have enough trouble sleeping at night.
73 de Mike, W4EF.......................
-----Original Message-----
From: notawc@juno.com [SMTP:notawc@juno.com]
Sent: Sunday, May 02, 1999 3:14 PM
To: towertalk@contesting.com
Subject: Re: [TowerTalk] A Different Take On Guy Wires?
On Sun, 2 May 1999 13:06:10 -0400 "Joe Subich, W8IK/4" <W8IK@ibm.net>
writes:
>
>
>
> >
> > On a related thread would not just one set of 1/4" EHS guys at the
> 40'
> > level be sufficient for a modest tribander type of installation?
> > Which would be better in that case, a pier pin base or solid
> concrete?
> > This would then negate the need for easy to damage Phillystran and
> > possibly even guy insulators. In Florida having everything
> grounded 6
> > ways to Sunday seems a wise move.
> >
>
> Most, if not all, of Florida is 100 MPH or 110 MPH territory. I
> would
> not consider leaving 20' of Rohn 45 above the guy point even with a
> small tribander (C-3, TH3, TA33, A3, etc.).
Why not? I dont even consider the above as real antennas. Rotary dummy
loads maybe.
Such an installation
> would
> be "pushing the envelope" for the tower strength at the guy
> attachment,
> the base, and in the middle of the lower span.
That does not agree with anything I have read or experienced. Please
explain your reasoning.
45G can handle at least 2.5 X their ratings just to get past the lawsuit
issues.
> 73,
> ... Joe Subich, W8IK/4 ex-AD8I
> <W8IK@IBM.NET>
>
>
> --
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>
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