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[TowerTalk] LM- 354 Failure

To:, <>
Subject: [TowerTalk] LM- 354 Failure
Date: Mon, 8 Jun 2009 19:49:17 EDT
List-post: <">>
I have had cable failure on one of my LM 470 towers as well.  Although  the 
cable was rusted, and many years old that failure was caused by another  
component in the tower system.  The real culprit was a failed bearing in  one 
of the cable pulleys.  Under load, this pulley locked up and acted as a  
brake and greatly increased the strain on the less then 100% cable.  I  
strongly recommend that you lower the tower, and with appropriate wood blocks  
the load off of each sections cables and inspect the pulley bearings.   You 
will have to disconnect the "down" cable to do this.
Going forward and along with regular lubrication of the cables, be sure to  
get some lubricant into the pulley bearings.  
Norm W4QN

Message:  2
Date: Mon, 8 Jun 2009 05:19:51 -0400
From: JP Lyet  <>
Subject: [TowerTalk] Crank-up tower limit
To:  "" <>
Message-ID:  <>
Content-Type:  text/plain;    charset=us-ascii;    format=flowed;   

Had a Tri-Ex LM-354-HDSP cable failure 2 years  ago.  Corrosion mostly,  
but actual cause is not known.   Otherwise flawless service for 10  
years.  In retrospect,  suspect the antenna load may have been a  
contributing factor as  between the 6 band yagi, T2X rotor  and mast,  
the total load  was ~200#, or 80% of max load rating for tower!
Tower was totalled and  recently replaced with identical unit.  Beam  
refirbed to like  new, but reluctant to use due to weight concerns.
Anyone else in the group  pushing a crank-up tower to ~ 80% of dead  
load limit on a regular  basis?  Any other pearls or advice ?  Suspect  
my beam  would be better served on a fixed tower installation and new  
tower  with a lighter unit.
(that being the case, anyone interested in a M-67B-3  can contact me  
off-line for specifics)
Tnx, 73
Paul /W3PL in  Pa.

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