TDR Schematic

[rmmrmm]

I´m looking for an schematic about Time Domain Reflectometer  ( TDR ) , to measure utp cable length.
I found an article in : http://www.elecdesign.com/Articles/ArticleID/6260/6260.html) , but is only an injector ,  you need an oscilloscope , not practice in the field an a little expensive.

Somone have any sugestion ??

Thanks in advance

[eSilviu]

i have an ideea:
measure capacitance betwen two wires of the utp cable
(i expect the capacitance to be 20pF..50nF)

there are many methods to measure low capacitors
- LC oscillator,
- charge/discharge the capacitor

i saw somewere on the web an capacimeter with 16F84 and display. some small modifications, and it should be ok

[rmmrmm]

Thanks , for your suggestion.
Is not the best way ( I tried before , and found 5% of error ).
But I decided to go on with capacity measure anyway , because a TDR is not a easy project for amateur ( need works at least in 200Mhz , for low distance resolution ).

Any suggestion aditional to respect , will be apreciated.