Raymarine E Series User Reference Handbook page 180

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 main fishfinder screen:
1. Press the PRESENTATION softkey.
2. Press the GAIN softkey.
3. Press the COLOR THRESHOLD softkey.
4. Use the rotary controller to select the required color threshold.
5. Press the OK button.
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
Note: TVG has no effect in fishfinder simulator mode.
1. From the main fishfinder screen, press the PRESENTATION
softkey.
2. Press the GAIN softkey.
3. Press the TVG softkey until the MAN option is selected.
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4. Use the rotary control to select the amount of Time Varied Gain
you want.
5. Press the OK button.
Fishfinder power
The power setting controls the power level of the transducer.
Power options:
• Auto. This is the default setting. When it is selected the DSM
automatically determines the required power setting based on the
current depth, speed, and (bottom) signal strength. .
• Manual. If you wish to manually adjust the power to suit current
conditions, you can adjust the power level between 0% and
100%, in 10% increments. Lower power levels are normally used
in depth ranges less than 8 ft. (2.4 m) and higher power levels are
typically selected for depths greater than 12 ft. (3.7 m).
Adjusting the fishfinder power
From the main fishfinder screen:
1. Press the PRESENTATION softkey.
2. Press the POWER softkey until the MAN option is selected.
3. Use the rotary control to select the amount of power you want.
4. Press the OK button.
The new values remain set even when you switch off the display
and are applied to all fishfinder windows.
Depth and distance with the fishfinder
You can use VRM markers and depth lines to help you determine
depths and distances in the fishfinder display.
The fishfinder display provides a number of features to help you
determine depths and distances. These features are illustrated and
described in more detail below:
E-Series Widescreen User reference