Furuno NAVNET 1823C - Manual (Page 159)

4. VIDEO SOUNDER OPERATION
4-13
4.6 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 Electrical inteference
other sounder
Types of interference
To reduce interference, do the following:
1. Press the [MENU] key.
2. Press the SOUNDER MENU soft key.
3. Select NOISE LIMITER, then press the EDIT soft key to show the noise
limiter window.
NOISE LIMITER
▲
¤ OFF
¡ LOW
¡ MEDIUM
¡ HIGH
▼
Noise limiter window
4. Use the trackball to select the degree of suppression desired (LOW,
MEDIUM, HIGH), or turn the noise limiter off.
5. Press the RETURN soft key followed by the [MENU] key to close the menu.
Turn the noise limiter circuit off when no interference exists, otherwise weak
echoes may be missed.