E Kafeman
Advanced Member level 2
A VNA and a time discriminator is an easy measurement method to analyze different types of cable faults but very unreliable for long cables which requires long time delay and real impedance/phase becomes hard to measure due to cable discontinuities. Using frequencies in GHz range makes it also almost impossible to get good time reference. An example about how a TDR instrument can be done with simple tools and almost no cost: TDR Circuit. It gives a more "hands on" understanding how these kind of instruments are working. Add some processing power and you have a professional TDR instrument.