Garmin G600 manual Ground Returns, Angle of Incidence

System Foreword

Sec 1

4.10.2.2Ground 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.

	Sec 2 PFD
	Sec 3 MFD
Sec 4	Hazard Avoidance
Sec 5	Additional Features
Sec 6	Annun. & Alerts
	Sec 7 Symbols
	Sec 8 Glossary
	Appendix A
	Appendix B Index

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 will provide 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.

4.10.2.3Angle of Incidence

The angle at which the radar beam strikes the target is called the Angle of Incidence. Incident angle (“A”) is illustrated below. 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.

4-84 Garmin G600 Pilot’s Guide 190-00601-02 Rev. E