Which of the following can be measured with an antenna analyzer?

An antenna analyzer is a versatile instrument that contains a variable frequency RF source and an impedance-measuring bridge. By measuring complex impedance across a range of frequencies, it can determine much more than just an antenna's standing wave ratio (SWR). It can be used to find a feedline's electrical length and velocity factor by identifying the specific frequencies at which a piece of coaxial cable acts as a short or open circuit. Furthermore, by coupling the analyzer to an LC circuit, such as a trap or tank circuit, you can easily find its resonant frequency by locating the point where the reactance drops to zero. Therefore, all of the listed choices are valid applications.