TM 11-5840-281-12-1
4-5.
SITE AND SHELTER REQUIREMENTS. (CONT)
Equipment siting limits are determined by display resolution, aggregate system accuracies, and mechanical scan limits of
antennas. Radar set group should be located between 400 and 6080 feet (122 and 1854 m) from td point and 100 and
750 feet (31 and 229 m) offset from centerline of runway. These limits form boundaries (one for right-of-runway, one for
left-of-runway) in which radar set group should be located to function properly for a single runway approach.
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Ideal runway approach coverage is obtained when the azimuth antenna scans 15 degrees (solid lines) to each side of the
rpl. When the situation warrants, the azimuth scan may be offset a maximum of 10 degrees (dotted lines) toward the
runway to provide better landing approach corridor coverage.
Notice that dimensions listed define a definite rectangle, but siting areas shown (page 4-4) have a corner of the rectangle
missing. The reason for this is that when radar set group is located less than 1,610 feet (491 m) from td point, the
maximum offset distance is limited by the precision approach (30-degree sector) scan of the azimuth antenna. During
precision approach, the azimuth scan must include the td point and the landing approach corridor. When the azimuth
antenna is offset 10 degrees (dotted lines), then 25 degrees of the azimuth scan will be on the runway side of the rpl and
will include the td point. Therefore, if a line is extended from the td point at an angle of 25 degrees to the clr, it will
intersect at a maximum offset distance of 180 feet (55 m) at 400 feet (122 m) from td and a maximum offset distance of
750 feet (229 m) at 1,610 feet (491 m) from td. These dimensions form the actual boundaries (page 4-4) for siting radar
set group.
4-5
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