Furuno CH-250 - Manual (Page 61)

3-11
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
Setting
0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 . . . . 10.0
Meters 3 8 20 40 60 100 130 160 200 250 320 . . . . 1000
Feet 10 30 70 130 210 330 410 520 660 820 1040 3280
Passi/braza 2 5 10 20 40 60 80 100 120 150 180 600
Hiro 2 5 10 20 40 60 80 100 130 170 210 . . . . 660
5. Press or to close the dialog box and return to the VERT menu.
6. To suppress reflections by the sea surface or plankton, select 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 Correct Level too high Distance too high
Figure 3-14 Examples of proper and improper TVG
3.11.2 Suppressing noise and interference
You may encounter occasional or intermittent noise and 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.
Interference rejector ON
Interference
(In this display,
interference shows
itself every 6˚.)
Figure 3-15 Appearance of interference