Raymarine e7D, Installation And Operation Handbook, Page: 164 / 270

14.8 Fishfinder sensitivity adjustments
The Adjust Sensitivity menu gives you access to features and
functions which enhance what is displayed on screen.
Sensitivity options include:
• Gain Mode
• Auto Adjust
• Color Gain
• TVG
• Color Threshold
• Power Mode
Sonar gain
The gain settings alter the way the DSM processes background
noise (also called clutter). Adjusting the gain settings can improve
the sonar image, however for optimum performance in most
conditions, we recommend that you use the auto settings.
The gain adjusts the return threshold (echo strength) above which
the fishfinder will show an object on the screen.
There are two gain modes:
• Auto
• Manual
Auto
In Auto mode, the DSM sonar automatically adjusts the gain setting
to suit current conditions. Any adjustments made apply to all
fishfinder windows using that particular frequency.
There are three Auto modes, each suited to different scenarios:
• Low (Cruising) is ideal for viewing fishfinder images with a
minimum of background noise as you are cruising to your fishing
spot. Only the strongest echoes are displayed.
• Medium (Trolling) is a slightly higher gain setting that displays
more detail. This is the default mode.
• High (Fishing) provides the most detail, but also displays the
most background noise and surface clutter.
Manual
If necessary you can set the gain controls manually, between a
value of 1 to 100 (default value is 75). This value 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 new values remain set even when you switch off the display,
they are applied to both the active window and any other fishfinder
windows with the same frequency.
Selecting automatic fishfinder gain
From the fishfinder application:
1. Select
Menu .
2. Select Adjust Sensitivity .
3. Select Gain Mode .
4. Select the Gain Mode menu so that Auto is highlighted.
Selecting Gain Mode will switch between Auto and Manual gain
modes
5. Go Back to the Sensitivity menu.
6. Select Auto Adjust .
7. Select the required Auto Gain mode.
Adjusting the fishfinder gain manually
From the fishfinder application:
1. Select
Menu .
2. Select Adjust Sensitivity .
3. Select Gain Mode .
4. Select the Gain Mode menu so that Man is highlighted.
5. Use the Rotary Control to adjust the gain to the required setting.
The new values remain set even when you switch off the display,
they are applied to both the active window and any other fishfinder
windows displaying the same frequency.
Fishfinder color gain
You can adjust the color gain to change the signal strength threshold
for the strongest color in your fishfinder display.
Color gain sets the lower limit for the strongest echo color. All
echoes with a signal strength above this value are displayed in the
strongest color. Those with a weaker value are divided equally
between the remaining colors.
• Setting a low value produces wide band for the weakest color, but
a small signal band for the other colors.
• Setting a high value gives a wide band for the strongest color, but
a small signal band for the other colors.
There are two color gain modes:
• Auto . In Auto mode the color gain setting is automatically
adjusted to suit current conditions. Any adjustments made apply
to all fishfinder windows.
• Manual . You can set the color gain manually, between a value
of 1 to 100.
Adjusting the fishfinder color gain
From the fishfinder application:
1. Select
Menu .
2. Select Adjust Sensitivity .
3. Select Color Gain .
4. Select the Color Gain menu so that Man is highlighted.
Selecting the Color Gain menu will switch between Auto and
Manual color gain.
5. Use the Rotary Control to adjust the Color Gain to the required
setting.
The new values remain set even when you switch off the display
and are applied to all fishfinder windows.
Fishfinder TVG (Time Varied Gain)
The Time Varied Gain (TVG) function reduces the amount of clutter
in the fishfinder display by varying the gain throughout the column of
water. This function is useful for reducing the appearance of ‘noise’.
• Increasing the TVG value increases the maximum depth to which
TVG is applied. A high value decreases the gain in shallow water
so that only the strongest echoes are displayed.
• Decreasing the TVG value reduces the maximum depth. A low
TVG value has little effect on gain in shallow water.
TVG adjustment can be made automatically or manually.
Adjusting the fishfinder time varied gain
From the fishfinder application:
1. Select
Menu .
2. Select Adjust Sensitivity .
3. Select TVG .
4. Select the TVG menu so that Man is highlighted.
Selecting the TVG menu will switch between TVG Auto and
Manual modes.
5. Use the Rotary Control to adjust the TVG to the required setting.
Note: TVG has no effect in fishfinder simulator mode.
Fishfinder color threshold
The color threshold setting determines the range of colors used on
screen. The effect of this is to set a color threshold below which
targets are not shown. For example a low setting would result in
only the strongest (orange and red) targets being displayed.
Adjusting the fishfinder color threshold
From the fishfinder application:
1. Select
Menu .
2. Select Adjust Sensitivity .
3. Select Color Threshold .
4. Select the Color Threshold menu so that the setting is
highlighted.
5. Use the Rotary Control to adjust the color threshold to the
required setting.
164 e7 / e7D / e95 / e97 / e125 / e127 / c95 / c97 / c125 / c127