The AN/MPN-1 was a mobile ground-controlled approach radar first used during the Second World War. This radar was employed to assist the process of directing aircraft over a predetermined glide path for safe approach to an airdrome runway under conditions approaching zero visibility. The AN/MPN-1 provided range and azimuth information on aircraft within a radius of 30 miles (48 km) with an operational ceiling of 4,000 feet (1,200 m). Communications were provided by the SCR-274 transmitter, and BC-342 receivers. A V-8 truck contained the system's two PE-127 power units (rated output of each 7.5-KW), one air conditioner unit, and equipment spare parts. The V-2 trailer contained the system's radar and communications sets.