Abstract: A radio system and method for monitoring and locating objects, including individuals, animals and articles, both locally and on a nationwide scale use monitoring base stations communicating by ID code with portable transponders which are secured to the objects to be monitored. The transponder responds to signals transmitted by the base, the latter indicating by an alarm the absence of a timely appropriate response from the transponder. The base is capable of performing and participating in homing techniques to locate a lost transponder. A list of the IDs of all transponders reported missing is distributed from a central source by nationwide communication to a network of radio stations, each station broadcasting the list in an encoded signal in repetitive sequence along with regular programming. Cruising vehicles of public safety departments operating locally nationwide are equipped with automatic monitors for receiving specially coded messages including IDs from transponders within their areas.