WV-2s, redesignated EC-121s in 1962, served from 1954 to 1965 in two "barrier" forces, one off each coast of the North American continent. The barrier forces consisted of 5 surface picket stations each manned by radar destroyer escorts and an air wing of WV-2s/EC-121s that patrolled the picket lines at 1,000–4,000 m (3,000–12,000 ft) altitude in 6- to 20-hour missions. Their objective was to extend early warning coverage against surprise Soviet bomber and missile attacks as an extension of the DEW Line.