Furuno GD-1700C - Manual (Page 158)

4. VIDEO SOUNDER OPERATION
4-14
4.8 Erasing Weak Echoes
Sediment in the water or reflections from plankton may be painted on the display
in green or light blue (color display) or “spots” on the background (monochrome
display). These weak echoes may be erased as below.
Weak
echoes
Appearance of weak echoes
1. Press the [MENU] key.
2. Press the SOUNDER MENU soft key.
3. Select SIGNAL LEVEL, and press the EDIT soft key to show the signal level
window.
SIGNAL LEVEL
¤ OFF
¡ SL1
¡ SL2
¡ SL3
¡ SL4
¡ SL5
¡ SL6
SIGNAL LEVEL
¤ OFF
¡ SL1
¡ SL2
¡ SL3
16-color display 8-color display Monochrome display
SIGNAL LEVEL
¤ OFF
¡ SL1
¡ SL2
Signal level window
4. Use the cursor pad to select level of erasure or OFF as appropriate. The
higher the number the stronger the echo that will be erased.
5. Press the RETURN soft key followed by the [MENU] key to close the menu.
Note:
Unlike “clutter,” signal level reduces echo colors. Therefore if you do not
wish to reduce echo colors use clutter instead.