BendixKing IN-862A System RDR-2100 - Manual (Page 29)

LOOKING ANGLE
The incident angle at which the terrain is illuminated has a direct bearing
on the detectable range and the area of illumination. A large incident
angle gives the radar system a smaller detectable range of operation
(due to a minimized reflection of direct radar energy). However, the illu-
minated area “A” is larger.
A smaller incident angle gives the radar a larger detectable range of
operation because of an increase of direct radar energy reflected from
the target to the antenna. The area of illumination (“A”) is smaller.
Concentration of the beam energy on a small area of terrain increases
the magnitude of the echo intercepted by the antenna. The resulting
detectable range is therefore increased for mountainous terrain; the
maximum distance at which this terrain can be monitored is greater
because of the more direct reflection (or radar echo) produced.
Illuminating the backslope of hills stretches the area of coverage beyond
the flat terrain coverage.
Effective Date: 9/98 RDR 2100 Pilot's Guide: Rev 1
25
Ground Mapping and Interpretation
RDR 2100 PG 3/12/07 3:45 PM Page 25