Raymarine C140w User Reference Handbook page 161

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.
4. Use the rotary control to select the amount of Time Varied Gain
you want.
5. Press the OK button.
Fishfinder power
The fishfinder power setting enables you to adjust the power of the
DSM sonar signal. This is useful for accommodating different water
depths and vessel speeds.
The power setting for the DSM sonar can be adjusted to suit
different conditions, such as water depth and vessel speed. By
default, the power setting is adjusted automatically to suit current
conditions, but the setting can also be adjusted manually if required.
• Lower power levels are suitable for depths of less than 2.4 m (8 ft).
• Higher power levels are generally more suited to depths greater
than 3.7 m (12 ft).
There are two power modes:
• Auto. In Auto mode, the power setting is automatically adjusted
to suit current conditions.
• Manual. You can set the power setting manually, between a value
of 1 to 100%, in 10% increments.
Using the fishfinder
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:
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