Final answer:
Ground clutter typically appears within a half-mile to a mile of the radar, affecting its performance. The effective air defense perimeter around a SAM site is typically estimated at 30 nautical miles. Calculating the distance an object is from radar can be done using the time it takes for the radar pulse to return.
Step-by-step explanation:
Ground clutter generally appears within a radius of a half-mile to a mile of the radar as a roughly circular region with a random pattern. This phenomenon affects radar performance by creating unwanted echoes and false readings. In an air defense context, such as around a confirmed SAM site or a possible SAM site, the effective perimeter for ground defenses is often estimated at around 30 nautical miles.
Radar systems function by sending out pulses of radio waves and detecting the echoes that return from objects. The distance to an object can be calculated by the time it takes for the pulse to travel to the object and back. For an aircraft radar, if a pulse reflected off an object is received 6x10-5 seconds (or 60 microseconds) after it was transmitted, the distance to the reflecting object can be calculated using the speed of light since radio waves travel at this speed.
As for the resolution of radar systems, at 500 MHz frequency, the smallest observable detail can vary but is typically related to the wavelength of the radar. Higher frequencies generally allow for finer resolution of details.