AN/MPN
Mobile ground-controlled approach radars introduced during World War II
AN/MPN is the US Military prefix designation for a group of mobile ground-controlled approach (GCA) radars first introduced during World War II. "MPN" is the Joint Electronics Type Designation System (JETDS) nomenclature for mobile (M, ground mobile systems), radar (P), navigational aid (N). The AN/MPN designation is then followed by a hyphen and a number to denote the sequence in which that particular system was developed and manufactured.
Variants
AN/MPN-1
Developed first by Gilfillan in the early 1940s, and later by Bendix Aviation, the system (called a "radio set") operated as a ground-controlled approach (GCA) system with a combined mobile military precision approach radar (PAR) and airport surveillance radar (ASR). It assisted in directing aircraft over a predetermined glide path for safe approach to an aerodrome runway under conditions approaching zero visibility. The system was introduced during World War II. The radars (PAR/ASR) provided range, azimuth and elevation information of aircraft within a radius of 10 miles (8.7 nmi; 16 km) for PAR and 30 mi (26 nmi; 48 km) for ASR.
The 15 kW PAR operated in the X-band frequency range while the 80 kW ASR operated in the S-band range. The azimuth antenna had a 1° beam width and a 2° height in elevation while the elevation antenna had a 3.6° width and 0.6° height with both antennas having a 30 RPM scanning rate. With a 20° horizontal azimuth beam width and a 7° elevation beam, the system had a 4,000-foot (1,200 m) operational ceiling.
A Diamond T 4-ton 6×6 truck (G-509) was the original prime mover hauling a 4-wheeled trailer which contained the bulk of the operational equipment. Also included on the Diamond T truck were two PE-127-A gasoline-driven power generators, providing 117-volt, 60-hertz electrical power, an air conditioner, and a spare parts box. High frequency (HF) and very high frequency (VHF) communications were provided by an SCR-274 transmitter, and BC-342 receivers.
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