Executive Summary
This procedure defines a test method for measurement of coaxial cable characteristic impedance, Z0. Throughout this document the shorter term cable impedance may be used.
Scope
The purpose of this procedure is to provide instructions for measuring 75 ohm coaxial cable impedance.
The cable input impedance as a function of frequency is calculated from a vector (magnitude and phase) return loss. The average of this input impedance across the desired frequency range is the cable impedance. This calculation may be automated using a computer connected to the vector network analyzer or the analyzer may have this function built in.
Benefits
When the cable impedance is near 75 ohms, input and output reflections are minimized improving system performance.
Intended Audience
This is a laboratory test procedure used for verification at the point of cable manufacture or to inspect finished cable performance.