Furuno DFF-3D - How to Smooth Echoes (Time); How to Apply Correction to the Speed of Sound; How to Show or Hide the Scale Box

4. OPERATION
4-9
4.4.5 How to smooth echoes (time)
If echoes are difficult to see because they appear “speckled,” use the echo smoothing
feature to suppress the speckling by time.
1. Select [Menu] from the menu icon bar to show the menu.
2. Select [Multibeam Sonar].
3. Select [Echo Smoothing (Time)].
4. Select [Low], [Medium] or [High] as required. The default setting is [Medium]. Se-
lect [OFF] to stop smoothing.
5. Select [Close] to close the pop-up menu.
4.4.6 How to apply correction to the speed of sound
Even though the sea bottom is flat, the left or right edge, up or down may be distorted.
To compensate for this problem, adjust the speed of sound.
Manual correction
1. Select [Menu] from the menu icon to show the menu.
2. Select [Multibeam Sonar].
3. Select [Sound Speed Correction], then enter a correction. The setting range is
-200 to +200.
4. Select [Close] to close the menu.
Automatic correction
1. Select [Menu] from the menu icon to show the menu.
2. Select [Multibeam Sonar].
3. Select [Temp.-based Correction], then select [ON].
Select [OFF] to remove the correction.
4. Select [Close] to close the menu.
4.4.7 How to show or hide the scale box
The scale box, shown at the bottom-left corner on the display, shows depth, current
range, and TX frequency. You can show the box as follows.
1. Tap the cross section display to show the pop-up menu.
2. Select [Scale Box] to show the scale box.