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Lossy Transmission Line Component Calculation

Lossy Transmission Line Component Calculation

Lossy Transmission Line Component Calculation

(OP)
I need to determine the R, L, C, and G of a lossy transmission line at various frequencies below 1 MHz.  I have only one access point at an end.  Any suggestions would be appreciated.  My first attempt was to determine the input impedance and set it equal to sqrt{(R+jwL)/(G+jwC)} and solve simultaneously for real and imaginary parts.  It seemed messy and tended to blow up.
Thanks

RE: Lossy Transmission Line Component Calculation

How long is the line ? At 1 MHz most likely the ohmic
parts are negligeable, unless the line is very long.

<nbucska@pcperipherals.com>

RE: Lossy Transmission Line Component Calculation

(OP)
This is not an ordinary transmission line.  It is actually an insulated pipe in the earth of unknown length.  The particular line that I am testing is about 250 feet long before it makes a connection to the main line;  it then continues several miles.

RE: Lossy Transmission Line Component Calculation

What are you trying to do ? Using TDR to trace the pipe ?
detect leakage or break ?

<nbucska@pcperipherals.com>

RE: Lossy Transmission Line Component Calculation

(OP)
Tracing pipe by injecting a signal and tracing the resulting magnetic field.  I am attempting to detemine the how different frequencies respond.

RE: Lossy Transmission Line Component Calculation

Public utilitis do this rutinelly -- why don't you find out
what they use.

You may also search for patent at wwww.USPTO.GOV

<nbucska@pcperipherals.com>

RE: Lossy Transmission Line Component Calculation

The telephone guys do this all the time.  Why don't you see if you can borrow a test set for DSL line trouble-shooting.  DSL frequencies can go up to several megahertz.  The better testsets will return all the values you are looking for.

Lewis

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