amateur radio direction finding (ardf, also known as radio orienteering, radio fox hunting and radiosport) is an amateur racing sport that combines radio direction finding with the map and compass skills of orienteering. it is a timed race in which individual competitors use a topographic map, a magnetic compass and radio direction finding apparatus to navigate through diverse wooded terrain while searching for radio transmitters. the rules of the sport and international competitions are organized by the international amateur radio union. the sport has been most popular in eastern europe, russia, and china, where it was often used in the physical education programs in schools.