Garmin gpsmap 4008 User Manual

Using Sonar

To adjust advanced sonar settings, press 

 while viewing a sonar screen.

Range—the range of the depth scale on the right side of the screen (

 or, to adjust manually, 

 

or 

.

Gain—controls the sensitivity of the sonar receiver (

 or, to adjust manually, 

 or 

). To 

see more detail, increase the gain. If the screen is cluttered, decrease the gain.
Frequency—selects how the frequencies appear on screen (

, 

, or 

).

Zoom—zoom in to a section of the Full Screen. The zoom is off, or set to 

, by default. 

Four options are available:

2x Zoom—twice the magnification. Select 

, 

, or 

 to set the depth range of the 

magnified area.
4x Zoom—four times the magnification. Select 

, 

, or 

 to set the depth range of the 

magnified area.
Bottom Lock—locks the zoom window to the bottom. Select 

, 

, or 

 to set the 

depth range of the magnified area.

Depth Line—quickly reference a specific depth (

 or 

). When 

 is selected, press up or 

down on the 

 (GPSMAP 4000 series) or touch and drag the line (GPSMAP 5000 series) to 

set the depth of the reference line.
A-Scope—creates a vertical flasher along the right side of the screen (

 or 

).

Sonar Setup—opens the Sonar Setup screen. See 

•