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Re: [TowerTalk] LMR400

To: <>
Subject: Re: [TowerTalk] LMR400
From: "K8RI" <>
Date: Thu, 27 Sep 2007 13:48:30 -0400
List-post: <>

> LMR400 has a minimum bend radius during use of 4
> inches.
> This tells me that it is ok to us it on a rotatable
> antenna as long as the minimum bend radius is 4 inches
> or more - that is, the loops around the mast have a
> minimum diameter of 8 inches.
> Is this ok?

Just my 02 cents.

Having usex LMR-400 almost exclusively  until I started switching over to 
LMR-600 I'd say using the minimum repeatable bend radius is not a good idea. 
It'll work, but going with more reduces the strain on the coax.  I use an 8" 
radius with two full turns around the tower with the extra flex version and 
would not want to use less with the regular version.  If you bend LMR 400 to 
a 4" radius it'll stay bent. That is an indication of stressing the cable 
materials with the likelyhood of work hardening the center conductor over 
time. Repeatable bending just means it can be bent and straightened like 
that more than once where as the minimum bend radius (I think it's 1.5") 
means don't bend this tight, straighten and bend again without expecting 
some damage to the cable.  I'd want to know what criteria they use for 
determining that minimum working radius and what they expect for lifetime 
when flexing like that.

Using regular LMR-400 I'd want that radius to be no less than 8" for 
something like a rotator loopand even then I'd use the extraflex for the 


Roger (K8RI)

> Thanks in advance.
> Jeff, W3KL
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