SCR-720 10 cm Radar
Improved SCR-520 developed for installation on P-61 (right), P-70 and DeHaviland Mosquito.
Wavelength and Function
10 cm radar for air search with beacon functioins and connections to IFF. Similar in purpose to SCR-520-A and B, but components are smaller and lighter in weight. Manufactured by Western Electric.
Research and Development By
Bell Telephone Laboratories
Operational Requirements
Number of Operators:1Weight:415 lb. less cables
Power Supply:125 amp, 27 v DC; inverter delivers 1520 w, 115 v. 1 ph, 400 cps
Performance Max. Reliable Range on:Bombers, at 10,000 ft:17,000 yd.Fighters at 17,000 ft:8,500 yd. Minimum range:100 yd. Range Accuracy:±10° full scale Angular Accuracy:Azimuth ±3° Elevation
Search
Ranges: 1, 10, 20, and 100 statute miles. Azimuth Search: 180° forward sector. Elevation Search: operator may select any one of 4 sectors: 0° to 0° (level), -5° to +5°, +5° to +20° and +20° to +50°. In later models the ranges are changed to 5 miles, expanded sweep (dog leg), 10 20, and 100 statute miles.
Antenna specifications
Dipole antenna with 29-inch paraboloid reflector (right) spinning at 360 rpm (2, 10, or 20 mi. radar) or 100 rpm (100 mi. radar or 10, 20, or 100 mi. beacon).
Half power basewidth: 10° azimuth and elevation.Gain: 340.
Transmitter Specifications
Frequency:3000 mc/sPusle Rate(pps):1500 RF Source:MagnetronPulse Rate Beacon:375 pps RF Lines: 7/8 inch stub Coax Pulse Legnth:0.75 µs Pulser Type:Rotary gapPulse Length, Beacon:2.5 µs RF Peak Power: 100-150 kwEnergy pp, Radar:0.08-.11 joules RF Average Power: .0.112-.17 kw
Receiver Specifications
Type:SuperheterodyneIF Band Pase:3 mc/s Stages:O-RF; 6-IFMixer:Crystal (IN21) Local Oscillator: 726ANoise, db above kt df:11-15 Intermed. Freq.:60 mc/s
Indication and Data Output
Operator Station (far right): 1 5-inch CRT with type-B scan and 1 5-inch CRT with type-C scan.
Pilot's CRT (near right): 1 -3-inch type B (20 and 100 mile search and 10, 20, and 100 mile beacon), or type C (2 and 10 mile search). Vertical scale on C-tube extends from -15° to +60°. C-tube shows only targets within limits of range dial setting. Pilot also has range meter.
Remarks
Equipment will operate under temperatures from -40°F to +122°F, with relative humidity as high as 90%.
Max.altitude for satisfactory operation: 30,000 ft.
SCR-520-B differs from SCR-520-A by the addition of beacon an