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Re: [TowerTalk] US Tower MA550 Coax Feedline

To: "Ripton, David" <RIPTOND@coned.com>
Subject: Re: [TowerTalk] US Tower MA550 Coax Feedline
From: "James C. Garland" <4cx250b@muohio.edu>
Date: Fri, 18 May 2007 14:22:33 -0600
List-post: <mailto:towertalk@contesting.com>
Dave, the different in loss between LMR400 and LMR600 for your 
application is not very much. Using the coax loss calculator at 
http://www.ocarc.ca/coax.htm
I find that, at 440 MHZ, with a 60 ft run up the tower, the losses 
for the two cables are as follows:

LMR400: 1.594 dB
LMR600: 1.02 dB


The difference is only about half a dB.  I'd think LMR600 would be 
far too stiff for a crankup tower. In fact, I'd be inclined to use 
LMR400 Ultaflex. I don't know how long the run is from your station 
to the tower, but that would be a good place to use the heavier stuff 
or, better yet, some heliax. You maybe could make up the half dB that way.

73,

Jim W8ZR



At 12:21 PM 5/18/2007, you wrote:
>Anyone have experience using LMR-600 Flex to feed a UHF antenna on a
>MA550 Tubular Tower? I plan on feeding 220 & 432  beams any need
>low-loss coax. I don't think 9913 or LMR 400 flex would give me a low
>enough loss figure.
>
>Dave Ripton K2SIX
>212-460-4852
>riptond@coned.com
>
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*************************
Jim Garland
Santa Fe, NM
www.w8zr.net
************************* 

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