The Radio Beacon is a piece of equipment in Call of Duty. It is only used in the level "Pathfinder". It is used to mark the point where Allied troops will parachute.
After taking out the German by the tree, the player is tasked with retrieving Sgt. Heath's legbag. It contains the radio beacon. After eliminating two more soldiers, the player will arrive to the field where they must plant the beacon. Shortly after, troops will begin parachuting from C-47s.