[TowerTalk] LM-470 variations

[NPAlex at aol.com]

I have had over the years three different LM-470 towers, and there were  some 
significant changes.  The most notable was the change from a single  heavy 
lift cable in the 1960's versions to double strung lift cable in later  models. 
(circa 1970).  These variations are easily recognizable in the fact  that the 
lift cable had a moveable block pulley as part of the assembly.   All had 
positive pull down, and common drum mechanism.  The later models  using the double 
lift cables on each section are superior in that the load is  more balanced 
and less chance of binding.  There were also changes in the  fabrication of 
tower end guides which appeared to be cost reductions as welded  components were 
eliminated.  My experience was the later versions resulted  in more slop in 
the fit and allowed more tower sway then the fitted and welded  guides.  There 
may have been more changes, but the above I think were the  most significant - 
note cable sizes changed as well, and the double lift system  used all the 
same size cable diameter.
 
My tower now is a US HD-589, and I think much better built and  rigged.  The 
level winding mechanism and the limit relays mounted at ground  level is a 
very nice feature.
 
Regards,
Norm W4QN
========================================================
 
Message: 3
Date: Sun, 23 Nov 2008 10:17:19 -0800
From: "Bob Selbrede,  K6ZZ" <k6zz at ccis.com>
Subject: [TowerTalk] LM-470 Variations
To:  towertalk at contesting.com
Message-ID:  <49299e2f.9e.69d4.252229984 at mail.ccis.com>
Content-Type: text/plain;  charset="iso-8859-1"

Hello,

In researching specification  information on the Tri-ex
LM-470 I see comments suggesting that the LM-470  has
undergone some design/specification changes over the years. 
Does  anyone have factual information regarding this?  Are
there differences  between the LM-470, LM-470D and LM-470E? 
Is the Tashjian Towers LM-470E  identical to the older Tri-ex
LM-470?  Anyone care to shed some light on  the subject?

Thanks!

73, Bob K6ZZ

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