A Paddac beacon was a device used by Peacekeepers on Leviathans. It was connected to the control collar and received a constant signal from the collar to indicate proper operation. When the signal stopped being received, the beacon would begin emitting a homing beacon to allow Peacekeepers to recapture the Leviathan.
The beacon was designed to be emitted throughout the body of the Leviathan, making it extremely difficult to jam or silence. It was also designed with an internal defense mechanism that would destroy mechanical objects that came nearby such as DRDs. ("I, E.T.")