Raymarine C140w - Manual (Page 159)

12.6 Fishfinder presentation options
The PRESENTATION softkey gives you access to a features
and functions which enhance the fishfinder display and provide
additional on-screen functionality.
Presentation options include:
• Gain settings to enhance display clarity.
• Power to the transducer.
• VRM features for measuring depth distance.
• Dual frequency view options.
• Scroll pause and resume.
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 main fishfinder screen:
1. Press the PRESENTATION softkey.
2. Press the GAIN softkey.
3. Press the GAIN softkey until the AUTO option is selected.
4. Use the trackpad to select the auto mode you want.
5. Press the OK button.
Adjusting the fishfinder gain manually
From the main fishfinder screen:
1. Press the PRESENTATION softkey.
2. Press the GAIN softkey.
3. Press the GAIN softkey until the MAN option is selected.
Using the fishfinder 159