A microwave locating reflectometer has been described which is capable of producing a plot of the (complex) reflection coefficient Γ against distance along a waveguide, and is thus able to discriminate between various individual reflections set up in a microwave component. No sharp pulses or step functions are required, and a plot is produced in real time without (digital) computation. The instrument is also capable of producing either a swept- or fixed-frequency Smith-chart display of the total reflection coefficient of the component.