. The Bell System technical journal . Fig. 60—AX/.\PS-4 Antenna. The SCR-520, SCR-717 and SCR-720 Antennas- The antenna shown in Fig. ol is typical of the type used with the SCR-520and SCR-720 aircraft interception (night fighter) airborne radar equip-ment, as well as the SCR-717 sea search and anti-submarine airborne radarequipment. The parabolic reflector is 29 inches in diameter and produces aradiation beam about 10° wide. The absolute gain is approximately 25db. RF energy is supplied to a pressurized emitter through a pressurizedtransmission line system which includes a rotary joint l
. The Bell System technical journal . Fig. 60—AX/.\PS-4 Antenna. The SCR-520, SCR-717 and SCR-720 Antennas- The antenna shown in Fig. ol is typical of the type used with the SCR-520and SCR-720 aircraft interception (night fighter) airborne radar equip-ment, as well as the SCR-717 sea search and anti-submarine airborne radarequipment. The parabolic reflector is 29 inches in diameter and produces aradiation beam about 10° wide. The absolute gain is approximately 25db. RF energy is supplied to a pressurized emitter through a pressurizedtransmission line system which includes a rotary joint located on the ver-so Written by J. F. Morrison, 314 BELL SYSTEM TECHNICAL JOURNAL tical axis and a tilt joint on the horizontal axis. Either vertical or hori-zontal polarization can be used by rotating the mounting position of theemitter. Vertical polarization is preferred for aircraft interception workand horizontal polarization is i)referred for sea search Fig. 61—SCR-520 Antenna. For aircraft interception the military services desired to scan rapidly alarge solid angle forward of the pursuing airplane, 90° right and left, 15°below and 50° above the line of flight. The data is presented to the opera-tor in the form of both B and C })resentations and for this purposepotentiometer data take-offs are provided on the antenna. The reflectoris spun on a vertical axis at a rate of 360 rpm and at the same time it is RADAR ANTENNAS 315 made to nod up and down about its horizontal axis by controllable amountsup to a total of 65° and at a rate of 30° per second. In the sea search SCR-717 equipment, selsyn azimuth position data take-offs are provided which drive a PPI type of indicator presentation. Therotational speed about the vertical axis in this case is either 8 or 20 rpmas selected by the operator. The reflector can also be tilted about itshorizontal axis above or below the line of flight as desired by the operator. It wUl be note
Size: 1396px × 1790px
Photo credit: © Reading Room 2020 / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1900, bookdecade1920, booksubjecttechnology, bookyear1
