Radar Observer Unlimited (ROU) Practice Exam

Pulse Repetition Rate sets how often the radar transmits pulses, which fixes the time between pulses. An echo has to return before the next pulse is sent to be assigned to the correct transmission; otherwise, range ambiguity occurs. Because of that, PRR determines the maximum unambiguous range the radar can measure. The relationship is roughly Rmax ≈ c/(2·PRR), where c is the speed of light. So increasing PRR shortens the maximum unambiguous range, while decreasing PRR extends it.

The minimum range is governed more by transmitter/receiver dead time and switching, not PRR. Target resolution depends on pulse width and bandwidth, not PRR. Clutter level is influenced by environment and processing, with PRR having an indirect effect in some cases but not defining it.