Furuno GP-1650F, GP-1650DF manual Suppressing Interference, Suppressing Low Level Noise

2.8Suppressing Interference

Interference from other acoustic equipment operating nearby or other electronic equip- ment on your boat may show itself on the display as shown in Figure 2-20.

To suppress interference, do the following:

1.Press the [MENU] key and the soft key

SOUNDER SETUP OPTIONS.

2.Select NOISE LIMITER and press the soft key EDIT to show the noise limiter win- dow.

NOISE LIMITER

▲

'OFF ™NL1 ™NL2

™NL3

▼

Figure 2-20 Noise limiter window

3.Press ▲ or ▼ to select degree of sup- pression desired; OFF, NL1, NL2 or NL3. The higher number the greater the degree of suppression.

4.Press the soft key RETURN and the [SNDR] key to finish.

2.9Suppressing Low Level Noise

Light-blue dots may appear over most of screen. This is mainly due to dirty water or noise. This noise can be suppressed by ad- justing CLUTTER on the SOUNDER SETUP OPTIONS menu.

When the sounder mode is Auto, the clutter suppression setting is fixed at AUTO. To sup- press low level noise in manual sounder op- eration do the following:

1.Press the [MENU] key and the soft key

SOUNDER SETUP OPTIONS.

2.Select CLUTTER and press the soft key EDIT to show the clutter window.

CLUTTER

▲

3

▼

Figure 2-22 Clutter window

3.Press ▲ or ▼ to select clutter rejection level desired; 0 (OFF) through 9. The higher the number the higher the degree of suppression. Note that weak echoes may not be displayed when the clutter cir- cuit is on.

4.Press the soft key RETURN and the [SNDR] key to finish.

Interference from	Electrical inteference
other sounder

Figure 2-21 Types of interference

Turn the noise limiter circuit off when no in-

terference exists, otherwise weak echoes Figure 2-23 Appearance of clutter may be missed.

2-7