Raymarine DS400X, Owner'S Handbook Manual

Page: 45 / 92

Chapter 4: Main Menu 35
GAIN
The gain, or sensitivity, of the display adjusts background noise by varying
echo strength for display. The value of the gain control determines the
strength above which echoes are displayed. If the gain is low only the
strongest echoes are displayed. As the gain is increased, weaker echoes (from
air bubbles, for example) are also displayed.
The automatic gain modes find the ideal sensitivity level for you, based on
depth and water conditions. Automatic gain modes take advantage of the
hardware’s advanced HDFI technology. As a result, the sounder typically
achieves a sharper image in any of the automatic gain modes than is possible
in manual mode.Automatic gain varies the gain throughout the water column
based on the current conditions.
The DS400/500X provides three pre-defined automatic gain settings:
•
AUTO FISHING
is the highest automatic gain setting. It gives the best
details of the targets you have located and is ideal for slow speeds and
drifting.
•
AUTO TROLLING
is a medium gain setting that is better suited for trolling
speeds.
•
AUTO CRUISING
is the lowest automatic gain setting, ideal for reducing
background noise or travelling to your fishing spot at high speeds.
•
MANUAL
gain should be set high enough to see fish and bottom detail but
without too much background noise. Generally, a high gain is used in
deep and/or clear water; a low gain in shallow and/or murky water.
The default setting is
AUTO FISHING
.
Color Gain
Color Gain determines how echoes of different strengths are displayed. 128
colors per palette are available, with the strongest signals displayed in colors
representing the strongest signals in the currently-selected palette. The Color
Gain control sets the lower limit (threshold) for the strongest signal and is
represented as a percentage of that strongest signal.
A lower Color Gain percentage means a stronger echo is required to be
displayed in the strongest signal colors. All echoes with a signal strength
above this value are displayed in darker colors. All echoes weaker than this
value are divided equally between the remaining colors.