Anechoic chamber reflection levels, as much as 50 dB down, can be measured at frequencies up to a few gigahertz, with broadband information derived from a single time-domain measurement. The technique has an advantage over frequency-domain methods because it can separate different reflections from each other, allowing any particular area of the walls to be studied in detail. The source of a particular reflection can be identified by its distance from the antennas, as well as direction, so that improvements can be made to the absorber arrangement.