North Carolina Radar Operator Recertification Practice Exam

The correct statement is that RADAR units are not always completely sensitive and selective in detecting the speed of an object nearby. This is due to several factors that can influence the performance of RADAR systems.

RADAR technology relies on the emission and reception of radio waves, which can be affected by environmental conditions, such as weather, terrain, and the presence of other objects. For instance, heavy rain can scatter the radio waves, leading to reduced sensitivity. Furthermore, nearby objects can cause interference, making it challenging for the RADAR to accurately measure the speed of a target.

The specifics of the RADAR unit itself also play a significant role in its performance. Different units come with varying specifications, which affect their range, resolution, and ability to filter out unwanted signals. Thus, while RADAR systems are designed to detect speed efficiently, they are not infallible and can encounter challenges that affect their accuracy and reliability.

Therefore, it's essential to understand that while RADAR units are advanced technological tools, they do not always operate with complete sensitivity and selectiveness, which confirms that the assertion is false.