Garmin G1000 Cockpit Reference Manual page 171

Ground Returns
The intensity of ground target returns depends upon
the angle at which the radar beam strikes the ground
target (Angle of Incidence) and the reflective properties
of that target. The gain can be adjusted so shorelines,
rivers, lakes, and cities are well-defined. Increasing gain
too much causes the display to fill in between targets, thus
obscuring some landmarks.
Angle of Incidence
The angle at which the radar beam strikes the target
is called the Angle of Incidence. Figure 10-29 illustrates
the incident angle ('A'). This directly affects the detectable
range, the area of illumination, and the intensity of the
displayed target returns. A large incident angle gives the
radar system a smaller detectable range and lower display
intensity due to minimized reflection of the radar energy.
190-00708-00 Rev. A
Figure 10-29 Angle of Incidence
Garmin G1000 Cockpit Reference Guide for the Socata TBM 850
A smaller incident angle gives the radar a larger
detectable range of operation and the target display will
show a higher intensity. Since more radar energy is
reflected back to the antenna with a low incident angle,
the resulting detectable range is increased for mountainous
terrain.
SECTION 10 – HAZARD
AVOIDANCE
10-19