[mastax]

A Network Analyzer is an instrument to analyze the performance of a network of electronic components. Vector means that it analyzes phase as well.

It can tell you the effective Resistance, Inductance and Capacitance of the network at various frequencies. This is useful for tuning radio antennas or filters, or identifying bad cables or connectors.

You can precisely measure the length of a cable from one end (by measuring the time for the signal to reflect).

You can use it as a signal generator to illegally jam your neighbors TV signal, as another commenter here noted.

Not many common uses for it unless you think amateur radio is common.

[riidom]

Thanks!