In radar operations, what does the button marked with 'TH' signify?

The button marked with 'TH' signifies Track Hold. This function is critical in radar operations, as it allows the operator to maintain a track on a target even if the target temporarily exits the radar's detection range or if there's a brief interruption in tracking. Engaging Track Hold freezes the current tracking data, ensuring that the information remains available for analysis or for resuming tracking once the target comes back into range. This capability is essential for maintaining situational awareness and ensuring the continuous monitoring of targets, especially in dynamic environments where objects can be lost momentarily from the radar's field of view.