Garmin GMR 21/41 Marine RADAR User Manual


 
2 GMR 21/41 Owner’s Manual
basIc oPeratIon > understandIng radar
Before transmission begins, the message “Spinning Up” is shown
while the radar antenna reaches nominal rotation speed. After the
message disappears, the radar begins painting an image.
Understanding the Radar Display
The Radar Page shows a status bar along the top, user-congurable
digital navigation data down the right side, a Heading Line, and
Range Rings. Soft keys that allow quick access to radar functions and
setting changes appear along the bottom of the page.
Range
Rings
Heading Line
Zoom scale
Ring separation
Soft
keys
Using Range Rings
Use the Range Rings to quickly determine the distance to a target.
The lower-right corner of the screen contains two scales. The scale
value represents the distance from the center of the radar display to
the outermost complete ring. The top scale represents this value. The
bottom scale represents the ring separation or the distance between
the Range Rings. Use the RANGE keys to zoom in or out. The tick
marks on the Range Rings are arranged with major tick marks at 30
degree increments and minor tick marks every ve degrees. The tick
marks can help in quickly determining the azimuth to a target.
3/4 nm
1/2 nm
1/4 nm
Heading Line
The Heading Line is shown from your current position along the path
of your current heading.