GPSMAP 392/398/492/498 Owner’s Manual 79
USING SONAR > SONAR TAB OPTIONS
Sonar Tab Options
When a GSD 22, GSD 21, or GSD 20 is connected to the
GPSMAP 392/398/492/498, the Sonar tab appears on the
Main Menu.
Show Numbers Option
To access and change a setting on the Sonar tab:
1. Press and hold ADJ/MENU to access the Main Menu. Use
the ROCKER to highlight the Sonar tab.
2. Using the ROCKER, highlight the sub tab and then the field,
and press ENTER.
3. Highlight the setting, and press ENTER.
4. Press QUIT to return to the Sonar Page or a previous page.
General Sub Tab
Use the General sub tab to select the keel offset, auto color gain,
automatic gain level, automatic scroll speed limit, and transducer
type. The available General sub tab options are as follows:
Keel Offset—used to offset the surface reading for the depth of
a keel. This makes it possible to measure depth from the bottom
of your keel instead of from the transducer’s location. Enter a
positive number to offset for a keel, or enter a negative number to
compensate for a large vessel that can draw several feet of water.
The Keel Offset reflects in the depth reading.
Keel Offset:
Transducer at
Surface Enter (+)
a positive number
to show depth from
bottom of keel.
Keel Offset: Transducer
at Bottom of Keel. Enter
a (-) negative number to
show depth from surface.
