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[TowerTalk] Crank Up Towers

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Subject: [TowerTalk] Crank Up Towers
From: (K7LXC)
Date: Thu, 18 Dec 1997 10:48:09 EST
In a message dated 97-12-17 18:44:49 EST, writes:

> 've been living in California ever since I've been liscensed and plan
>  on
>  relocating to the east coast (originally from Gettysburg area). I've
>  never had
>  to deal with any severe weather out here.  How well do crank up towers
>  survive
>  in the Pa./Md. area either guyed or free standing. Sure do hate the
>  thought of
>  dealing with a crank up if it gets twisted up. Any comments appreciated.
Hi, Jay --

     The big difference is that anything within 100 miles of the Atlantic
Ocean is classified as being close to hurricane oceanline and subject to BIG
winds. While PA typically has a low wind speed rating of 70 MPH (the lowest
rating they give), NJ can be up to 85 MPH and NC can be up to 110 MPH. When
you decide where you'll wind up, give me the counties that you're considering
and I'll look them up in the TIA-222 (THE tower standard).

     The difficulty is that crank-ups are typically rated from the factory
lower than the 70 MPH minimum, usually 50 or 60 MPH. So if you're going to get
a building permit, your tower will have to be PE stamped for whatever wind
speed the local building department wants. You'll have to talk to the
manufacturer for more specific information and availability of documentation.

    Many current towers have 'positive pull-down' which allows you to crank
them down even if the wind is blowing and putting pressure on the sections.

    BTW, currently my "Up The Tower" column in CQ Contest magazine has been a
multi-part series on tower structures including crank-ups for the last couple
of months. I also have a couple of reprints on crank-up/wind load articles
that'll give you some answers. A reprint of the whole tower series will be
available in a couple of months at the conclusion of the topic. Send an SASE
for a catalog of reprints and products. (TOWER TECH, Box 572, Woodinville, WA,

73,  Steve  K7LXC

     TOWER TECH -- professional tower supplies and services for amateurs

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