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[TowerTalk] More antenna woes!

To: <towertalk@contesting.com>
Subject: [TowerTalk] More antenna woes!
From: w7ni@teleport.com (Stan Griffiths)
Date: Wed, 28 May 1997 03:20:22 -0700 (PDT)
>A couple of months ago, I posted a message requesting hints and suggestions
>before installing my new T2X rotor in my Rohn HDBX48 self-supporting tower.
>I am turning a KLM KT34XA Tri-bander.
>
>I received several great suggestions which I used when the new rotor was
>installed (Thanks all!) There was some question if the T2X would have enough
>clearance to turn in the top section without mounting the rotor plate up
>side down. There was plenty of clearance and after the rotor plate was
>redrilled to accept the T2X, the installation went smooth.
>
>Since that time, we have experienced quite a few days with very high winds
>and the KT34XA's mast turned in the rotor (No, I didn't pin it as I wanted a
>fail-safe link.) I live in Harrison County, Iowa, on a farm.
>
>Yesterday was a fine day for antenna work so me and a couple friends decided
>to reposition the antenna to the proper heading. While inspecting the tower
>on the way up, we found that THREE of the X-braces had rivits that had
>sheared off and one X-brace had actually broke in half right up near the
>rotor shelf!! Luckily, the tower is installed with the tilt-over base and
>this is the way I plan to disassemble the whole mess as it is NOT safe to
>climb in it's current condition!
>
>I plan to replace the top two sections (the rest of the tower is in
>excellent shape) and reinstall the T2X rotor and shelf at about the 16ft
>level of the tower or possibly even lower, where the torque will be
>distributed to a MUCH stronger section of the tower, and using a LONG mast
>to rotate the antenna through the thrust bearing.
>
>Does anybody know where I can purchase only the top two sections of the
>HDBX48 tower??  Any other hints that I should consider before putting this
>tower back up? Steve??
>
>Thanks in advance.
>
>73, 
>
>Chuck Sudds  K0TVD
>Missouri Valley, IA  USA

Chuck,

I would seriously consider NOT putting it back up.  The entire BX series of
towers is rated to take beams with a MAXIMUM boom length of 10 feet.  Your
KT34XA SERIOUSLY overloads it.  The BX series is simply not made to take the
twisting forces that long boom antennas put on it.  All of this is clearly
pointed out in the Rohn catalog that lists the BX series of towers.

Stan  w7ni@teleport.com


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