Hi,
same approach Peter mentioned is used by S58A and S52O with their 60m (200')
rotary self-supporting towers. Actually Boris and Karl both used main bodies
of 60+ m tall cranes, with bearings and rotating system embedded into
fundation. Sorry no pics available here, but you may asks those tower owners
directly (s58a@guest.arnes.si or drago.bucar@biro-bonus.si ).
73 Mirko, S57AD
----- Original Message -----
From: "peter.voelpel" <df3kv@t-online.de>
To: "'Kelly Taylor'" <ve4xt@mts.net>; "'Phil Camera'" <kb9cry@comcast.net>;
<TowerTalk@contesting.com>
Sent: Friday, January 13, 2006 4:58 PM
Subject: Re: [TowerTalk] Making a self-supporting tower rotate
>
> The best approach is to use slewing bearings at the bottom of the tower.
> This freestanding, 40m high, rotatable tower of a fellow ham
> with stacked long boom quads works flawless for more the 20 years:
>
> http://www.pbase.com/df3kv/image/46485734
>
> http://www.pbase.com/df3kv/image/46485728/original
>
> those bearings are obtainable pretty cheap at crane companies
>
> 73
> Peter, DF3KV
>
>
> -----Original Message-----
> From: towertalk-bounces@contesting.com
> [mailto:towertalk-bounces@contesting.com] On Behalf Of Kelly Taylor
>
> My big fear with a tower such as this is that instead of multiple weak
links
> (ring rotors), where perhaps one antenna bites it, you have one big weak
> link that would make the whole assembly bite it. The other angle that is
> perhaps not been explored either is the capacity of the tower to accept
> additional loads along its length.
>
> If I recall correctly, the Big Bertha tower worked because the entire
tower
> base was inserted into the bearings which were held down by lots of
concrete
> and because the design assumed from the start multiple antennas from top
> down.
>
> _______________________________________________
>
>
>
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