Hi, Gene.
Thanks for the URL.
Got out the data for my Trylon and antennas and put stuff in,
including the mast. Got basically the same overall figures as by other
means.
It was interesting to note the Kips going down the tower showing where
the tower would go if stressed to the limit, right in the middle
(30-40' down on 80').
If it's designed right a tower of this sort will collapse in the
middle at over stress, since the base had better not be moving at all.
Was also interesting to see that at collapse, the overturning moment
was only about a third of what it would take to move my base.
According to the figures, my setup would have ridden out Hurricane
Fran at this distance from the coast (80MPH out in the open at RDU
airport), with a small margin of safety, tho the antennas probably may
have been damaged. Have to take off 16 feet down at the coast tho.
Also did 1/2 inch radial ice (estimated) and 50 mph, which it did NOT
survive.
Did 1/2 radial ice and 25 mph, which it DID survive.
----- Original Message -----
From: "EUGENE SMAR" <ersmar@comcast.net>
To: "Pete Smith" <n4zr@contesting.com>; "TowerTalk"
<Towertalk@contesting.com>
Sent: Thursday, June 26, 2003 3:49 PM
Subject: Re: [TowerTalk] Trylon software
> Pete:
>
> Agreed. In the version of the posting that I did NOT send out
I had
> included details of my antennas and what method I used in the model.
I
> thought better of providing this info for fear it may be misapplied.
I will
> say that I took a conservative approach when I modeled my
installation.
>
> However, what the Trylon software DOES demonstrate is that one
gets
> dramatically different results when assuming the antenna elements
are round
> vs flat plate. It also shows what happens to the stresses on a
selected
> tower when the antenna load is moved up the mast. One can see how
easily a
> tower can fail by installing a significant antenna sail area ten
feet above
> the top of the tower. Plus, at least in the model of my tower and
antennas,
> the first tower segment to fail is NOT the bottom one. Interesting.
>
> BOTTOM LINE: Caveat Amateur.
>
> 73 de
> Gene Smar AD3F
>
>
>
> ----- Original Message -----
> From: "Pete Smith" <n4zr@contesting.com>
> To: "EUGENE SMAR" <ersmar@comcast.net>; "TowerTalk"
> <Towertalk@contesting.com>
> Sent: Thursday, June 26, 2003 2:11 PM
> Subject: Re: [TowerTalk] Trylon software
>
>
> > At 12:03 PM 6/26/03 -0400, EUGENE SMAR wrote:
> > >TT:
> > >
> > > I found an interesting piece of software on the Trylon
Titan web
> page:
> >
>http://www.trylon.com/lightdutytowers/selfsupporttwrs_size_towercalc.
asp
> .
> > >It's the program Trylon use to determine whether a selected tower
will be
> > >adequate for a combination of proposed antenna loads. You'll
need to
> input
> > >the antennas' wind area and other parameters regarding the
physical
> > >arrangement on the mast.
> > >
> > > I suggest you read the instructions and thoroughly
understand them
> (and
> > >the caveats) before you apply them to a proposed configuration of
TRYLON
> > >TITAN TOWERS (emphasis intended.) If nothing else, you can see
the
> effect
> > >of increasing antenna mounting height on the reactions at each
section of
> > >tower.
> > >
> > >73 de
> > >Gene Smar AD3F
> > >P.S. Don't forget to include the wind area and weight of your
mast.
> >
> >
> > And K7NV would be disappointed if I didn't also caution to be
careful that
> > the antenna wind area figures you use are calculated on the same
basis as
> > the numbers that Trylon uses to rate its towers. Combining apples
and
> > oranges can result in trying to put as much as 1.5 times the rated
amount
> > of antenna area on the tower.
> >
> > 73, Pete N4ZR
> > The World HF Contest Station Database was updated 17 June 03.
> > Are you current? www.pvrc.org/wcsd/wcsdsearch.htm
> >
> >
> >
>
> _______________________________________________
>
> See: http://www.mscomputer.com for "Self Supporting Towers",
"Wireless Weather Stations", and lot's more. Call Toll Free,
1-800-333-9041 with any questions and ask for Sherman, W2FLA.
>
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>
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