How to test twisted pair (ethernet) cable length


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  1. #1
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    Default How to test twisted pair (ethernet) cable length

    I was wondering if anyone knows how some of the handheld testing devices, like the (Fluke NetTool or now, the Linkrunner series http://www.flukenetworks.com/enterpr...rk-Auto-Tester ) test cable length? On the older NetTool device, I find the measurement helpful, but not extremely accurate. For instance, on a 14.1 feet, I get a measurement of 16 feet with the NetTool. This is close enough for me, to help figure out where old wiring on a 36 acre facility goes. Just wondering how they do it.
    http://www.scalerobotics.com

  2. #2
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    Default Re: How to test twisted pair (ethernet) cable length

    Google 'Time Domain Reflectometer'

  3. #3
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    Default Re: How to test twisted pair (ethernet) cable length

    Quote Originally Posted by ScaleRobotics View Post
    On the older NetTool device, I find the measurement helpful, but not extremely accurate. For instance, on a 14.1 feet, I get a measurement of 16 feet with the NetTool.
    Are you saying the length of the cable from one end of the sheath to the other is 14.1 feet ?

    If so the 16 feet measurement could well be correct as the cable is twisted therefore longer. also each pair has a different twist ratio therefore each pair will yeild a different results.

    Take two peices of single wire each 10 feet long, tie one end to a chair, put the other in the chuck of a cordless drill and twist it up. then see how long the resultant twisted pair is, it certainly wont be 10 feet.
    Keith

    www.diyha.co.uk
    www.kat5.tv

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