Furuno GP-3500F - Manual (Page 191)

11. VIDEO SOUNDER OPERATION
11-19
11.7 Reducing Interference
Interference from other acoustic equipment operating nearby or other electronic
equipment on your boat may show itself on the display as shown below.
Interference from
other sounder Electrical interference
Types of interference
To reduce interference, do the following:
1. Press the [MENU] key to show the main menu.
2. Press the [9] key to show the ECHO SOUNDER SETUP menu.
3. Press the [2] key to show the NOISE LIMITER window.
NOISE LIMITER
1. OFF
2. NL1
3. NL2
4. NL3
Noise limiter window
4. Rotate the [ENTER] knob to select degree of suppression (NL1, NL2, NL3)
or turn the noise limiter off.
NL3 provides the greatest degree of suppression.
5. Press the [ENTER] knob.
6. Press the [MENU] key several times to close the menu.