Furuno FSV-30, Operator'S Manual

Page: 48 / 190

2. HORIZONTAL MODE
2-18
2.9 Rejecting Sonar Interference and Noise
While observing the sonar picture, you may encounter occasional or intermittent
noise and interference. These are mostly caused by on-board electronic
equipment, engine or propeller noise, or electrical noise from other sonars being
operated nearby.
2.9.1 Identifying noise source
To eliminate noise effectively, you should first identify the noise source as
follows:
1. Stop transmission on the TEST menu, referring to page 10-7, and turn on the
power of all on-board equipment one by one while observing the picture. If
noise appears on the sonar display, that equipment is emitting noise. Check
the offending equipment’s ground and installation.
2. Run the boat at various speeds to check if the noise is speed dependent.
If neither of the above two steps has effect on the picture, adjust one of the
following:
2.9.2 Interference rejector
This control is similar to the interference rejector on echo sounders and radars. It
is effective for rejecting random noise and sea surface reflections in rough sea
conditions. Set it so that noise is just eliminated. Do not use an unnecessarily
high setting since it may also reject small wanted echoes.
1. Press the [MENU] key to open the menu.
2. Select the H-SCAN SETTING menu and press the [MENU] key.
3. Select INT REJECT and press the [MENU] key.
4. Adjust setting from the dialog box as appropriate and press the [MENU] key.
The setting range is 0-3. The higher the setting the greater the degree of
interference rejection.
5. Select QUIT and press the [MENU] key to conclude.
6. Select QUIT at the top of the menu screen and press the [MENU] key to
close all menus.