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Re: [TowerTalk] antenna location for hurricane

To: Alex Malyava <alex.k2bb@gmail.com>
Subject: Re: [TowerTalk] antenna location for hurricane
From: Mickey Baker <fishflorida@gmail.com>
Date: Thu, 25 Aug 2011 18:22:16 -0400
List-post: <towertalk@contesting.com">mailto:towertalk@contesting.com>
In high winds, wires tend to find points of physical resonance in the wind
and apply large pressures against the mechanical attachments. If your cables
are like mine, they're secured with tape, wire wraps and perhaps solid wire
bindings.

Any slack in those cables (like those for feedlines on a retracted
telescoping tower or you rotor loop) will mechanically wear at ponts of
abrasion to the point that they will be damaged and/or attachment points
will fail. The first failure might cause cascaded failure - the next thing
you know you have 10 pounds of coax or guy wire loose and whipping around in
a 100MPH wind. That would hurt, break windows, overall a Bad Thing.

Can you imagine driving down the highway at even 60 miles an hour, throwing
20' of coax out the window and holding on to the other end?

(Not safe, don't do this, all you wacky experimenters!)

I had a dipole fail in Wilma - the remaining RG8X feedline looked like I had
taken a razor knife and sliced it up the side to the center conductor for 50
feet. There was no center insulator, but the Dacrons ropes wer still
attached to the end insulators, as was 18 inches or so of #14
Copperweld. Everything else was gone. My 6' wooden fence had stripes on it
from things hitting it, I presume some of it was my dipole.

Yeah, hurricanes make a circle on the map, but locally, where you are at any
moment, the winds will be highly variable because of the interaction with
the ground. Hope for the best, plan for the worst case.

The suggestion to put your antenna in your basement is the best I've heard.

Even the OptiBeam isn't indestructable - but it is a nice antenna!

Mickey N4MB

On Thu, Aug 25, 2011 at 4:31 PM, Alex Malyava <alex.k2bb@gmail.com> wrote:

> What exactly do you mean under "Secure everything, including your rotor
> loop or any wires that would whip
> around..." ?
>
> I dont have BIG antennas here. I have 30' of Rohn 25 on a concrete base
> secured to the house at 18' level.
> There is Yaesu 450 turning short mast with small (size of 15m beam) 2
> element five-bander on it.
> Here it is  - http://public.fotki.com/malyava/2010/30-mast/photo-10.html
>
> The only thing I can think of is to go to the roof and loosen rotator
> clamp, so the mast will rotate freely and would not break the rotator...
>
> Is it bad idea?
>
> Anything else I can do?
>
> I hope for the best, but I dont believe that this antenna will survive 95
> mph wind gusts...
>
> Alex K2BB,
> Northern Jersey
>
>
> On Thu, Aug 25, 2011 at 2:36 PM, Mickey Baker <fishflorida@gmail.com>wrote:
>
>>
>> Secure everything, including your rotor loop or any wires that would whip
>> around, make your best guess and hunker down.
>
>


-- 
Mickey Baker
Fort Lauderdale, FL
“Tell me, and I will listen. Show me, and I will understand. Involve me, and
I will learn.” Teton Lakota, American Indian Saying.
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