Garmin Flight Deck 100 Manual De Usuario

®

190-00728-04 Rev. A

360

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 the gain too much causes the display to fill
in between targets, thus obscuring some landmarks.

Cities normally provide a strong return signal. While large buildings and structures provide good returns,

small buildings can be shadowed from the radar beam by the taller buildings. As the aircraft approaches
and shorter ranges are selected, details become more noticeable as the highly reflective regular lines and 
edges of the city become more defined.

Bodies of water such as lakes, rivers, and oceans are not good reflectors and normally do not provide

good returns. The energy is reflected in a forward scatter angle with inadequate energy being returned.
They can appear as dark areas on the display. However, rough or choppy water is a better reflector and
provides stronger returns from the downwind sides of the waves.

Mountains also provide strong return signals to the antenna, but also block the areas behind. However,

over mountainous terrain, the radar beam can be reflected back and forth in the mountain passes or off 
canyon walls, using up all or most of the radar energy. In this case, no return signal is received from this
area, causing the display to show a dark spot which could indicate a pass where no pass exists.