What equipment is primarily used to determine the direction and location of a signal?

The primary equipment utilized to determine the direction and location of a signal is Direction Finding (DF). DF systems are specifically designed to detect the angle of arrival of a radio signal, allowing operators to pinpoint its source. This capability is essential in electronic warfare as it enables the identification of adversary communications and radar emissions.

DF involves the use of antennas and triangulation techniques to establish the origin of signals, which is critical for situational awareness and tactical decision-making. This direct focus on locating signals differentiates DF from the other options, which have broader roles in the information-gathering and intelligence analysis processes.

For example, while Electronic Warfare Support (ES) refers to the collection and analysis of electromagnetic emissions for situational awareness, it does not inherently involve the precise directional capabilities of DF equipment. Similarly, Signal Intelligence (SIGINT) encompasses intelligence derived from signals, but it is a broader category that includes the analysis of intercepted communications rather than the direct location of signals. Communication Intelligence (COMINT) specifically deals with intercepted communications but does not focus on the localization aspect that DF provides.

In summary, Direction Finding is specialized in determining the source direction and location of signals, making it the correct choice for this question.