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Old 11th Oct 2018, 12:44 pm   #25
terrykc
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Join Date: Nov 2010
Location: North Hykeham, Lincolnshire, UK.
Posts: 515
Default Re: Determining Zo for coax cable

Quote:
Originally Posted by Skywave View Post
Unfortunately, TDRs are expensive items of equipment ...
They are? You can build one quite cheaply.

There is (or was) a $10 kit for this one including PCB and additional voltage regulator: http://www.epanorama.net/circuits/tdr.html

These might also be of interest: https://www.youtube.com/watch?v=I1gfUNh5PJQ

https://www.qsl.net/g4usp/Time%20Dom...ometer/TDR.htm

I did find some more but the links to the schematics no longer work!

Obviously these designs don't include all the bells and whistles that you would find on a professional instrument such as integral display, entry of velocity of propagation to match cable manufacturer's specifications and accurate measurement of cable length and fault location(s) but that is not what is being asked for here.
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