Basic Antenna Tilt Setup - Garmin GTN 725 Pilot's Manual

Foreword
Getting
Started
Audio &
Xpdr Ctrl
Com/Nav
FPL
Direct-To
Proc
12.3.4
Charts
The following discussion is a simple method for setting up the weather radar
Wpt Info
antenna tilt for most situations. It is not to be considered an all encompassing
setup that will work in all situations, but this method does provide good overall
Map
parameters for the monitoring of threats. Ultimately, it is desired to have the
antenna tilted so that the bottom of the radar beam is four degrees below parallel
Traffic
with the ground. The following discussion explains one way of achieving this.
Terrain
With the aircraft flying level, adjust the antenna tilt so ground returns are
displayed at a distance that equals the aircraft' s current altitude (AGL) divided
Weather
by 1,000. For example, if the aircraft is at 14,000 feet, adjust the tilt so the front
edge of ground returns are displayed at 14 NM. Note this antenna tilt angle
Nearest
setting. Now, raise the antenna tilt 6º above this setting. The bottom of the radar
beam is now angled down 4º from parallel with the ground.
Services/
Music
Practical Application Using the Basic Tilt Setup
Utilities
At this point, when flying at altitudes between 2,000 and 30,000 feet AGL,
any displayed target return should scrutinized. If the displayed target advances
System
on the screen to 5 NM of the aircraft, avoid it. This may be either weather or
ground returns that are 2,000 feet or less below the aircraft. Raising the antenna
Messages
tilt 4º can help separate ground returns from weather returns in relatively flat
Symbols
terrain. This will place the bottom of the radar beam level with the ground.
Return the antenna tilt to the previous setting after a few sweeps.
Appendix
12-38
Index
MPEL
Boundary
11' for 12" antenna
Figure 12-48 MPEL Boundary

Basic Antenna Tilt Setup

GTN 725/750 Pilot's Guide 190-01007-03 Rev. C