Measuring the characteristic impedance
The
characteristic impedance
is one of the main parameters of any coaxial cable.
Usually, its value is printed on the cable by the manufacturer. However, in certain cases
the exact value of the characteristic impedance is unknown or is in question.
To measure the characteristic impedance of a cable,
1. Connect a non-inductive resistor
to the far end of the cable. The exact
value of this resistor is not important.
However, it is recommended to use 50 to
100 Ohm resistors.
Example 1: 50-Ohm cable with 100
Ohm resistor at the far end.
Example 2: Unknown cable with 100
Ohm resistor at the far end.
2. Enter the R,X chart mode and make
measurement in a reasonably large
frequency range (for instance, 0 to 55
MHz).
Example 1:
50-Ohm cable
Example 2:
Unknown cable
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