Sonar Gain; Setting The Gain Automatically - Garmin GPSmap 585 Plus Owner's Manual

Sonar Gain

The Gain control function amplifies the signal received from the sonar
returning echoes. The signal strength from the echoes is stronger in shallow
water than in deeper water due to the lesser distance the echo has to travel
back to the transducer. The Gain can be operated in "Manual" or "Auto"
mode. In "Auto" mode, the signal received from the echoes is automatically
amplified. In "Manual" mode, the volume control setting is manually adjusted
according to the depth range and the underwater conditions.
If the Gain control is set too low, the signals received from the returning
echoes will be weak, reducing the signal strength and the amount of detail
recorded on the screen. The Gain setting controls the sonar receiver's
sensitivity to compensate for water depth and water clarity. Increasing the
Gain shows more details, and decreasing the Gain reduces screen clutter.
This can be corrected by gradually increasing the volume on the Gain control
setting until more details appear on the display screen.
If the Gain control is set too high, the screen will become cluttered as too
many signals are received. This can result in a failure to detect which of these
are fish targets. It can be corrected by gradually decreasing the volume on the
Gain control setting until less clutter appears on the screen.
NOTE: Setting the gain on one sonar view applies the setting to all the views.
Gain too low Gain too high
16
Gain proper

Setting the Gain Automatically

NOTE: To set the gain on the split-frequency screen, you must set each
frequency separately.
1 From a sonar view, select GAIN.
2 Select > Enable Auto Gain.
3 Select an option:
• To display higher-sensitivity, weaker sonar returns with more noise
automatically, select Auto High.
• To display medium-sensitivity sonar returns with moderate noise
automatically, select Auto Med.
• To display lower-sensitivity sonar returns with less noise automatically,
select Auto Low.
GPSMAP 585 Plus
®