Suppressing Noise And Interference - Furuno CH-300 Operator's Manual

4. Press ◄ or ► to adjust TVG distance, considering sea conditions. The larger the figure
the greater the distance at which the TVG works.
TVG Distance
0
Setting
Meters 3
Feet 10
Passi/braza 2
Hiro 2
5. Press ▲ or ▼ to close the dialog box and return to the VERT menu.
6. To suppress reflections by the sea surface or plankton, choose TVG LEVEL and press
►.
7. Press ◄ or ► to adjust TVG LEVEL, considering sea conditions. The larger the figure
the less the gain over distance.
8. Press the MENU key to register your selection and close the menu.
Wrong
3.12.2

Suppressing noise and interference

You may encounter occasional noise or intermittent interference as shown below. This is
mostly caused by electrical equipment, engine, propeller noise from own ship, or noise from
other sonars being operated nearby. If interference appears, turn on the interference
rejector in the COM1 menu to suppress it. Note that the interference rejector cannot be
turned on/off independently for each frequency in case of the dual-frequency display.
0.5 1.0 1.5 2.0
8 20 40 60
30 70 130 210
5 10 20 40
5 10 20 40
Correct
Examples of proper and improper TVG
Interference rejector ON
Appearance of interference
3. VERTICAL SCAN MODE
2.5 3.0 3.5 4.0
100 130 160 200
330 410 520 660
60 80 100 120
60 80 100 130
Level too high
Interference
(In this display,
interference shows
itself every 6°.)
4.5 5.0 . . . . 10.0
250 320 . . . . 1000
820 1040 3280
150 180 600
170 210 . . . . 660
Distance too high
3-11