What spacing is required when separating aircraft from prominent obstructions less than 40 miles from the radar antenna?

The requirement for spacing when separating aircraft from prominent obstructions less than 40 miles from the radar antenna is 3 miles. This specific distance is established to ensure aircraft safety by providing a buffer against obstructions that could impact flight paths.

Maintaining 3 miles of separation allows for adequate clearance for aircraft in various flight conditions, considering factors such as radar coverage limitations and the potential for signal inaccuracies that could arise due to terrain or man-made structures. Prominent obstructions close to the radar antenna pose significant risks due to the possibility of reduced radar effectiveness and signal distortion, hence the rationale behind this precise minimum separation requirement to uphold safety standards in aviation operations.