Furuno GD-1700C - Manual (Page 153)

4. VIDEO SOUNDER OPERATION
4-9
4.4 Manual Sounder Operation
Manual operation is useful for observing fish schools and bottom using fixed gain
setting.
The gain, range and range shifting functions used together give you the means
to select the depth you can see on screen.
4.4.1 Selecting the manual mode
1. If not displayed, press the [HIDE/SHOW] key to show the sounder soft keys.
2. Press the AUTO/D. BOX soft key to show the auto mode window.
3. Select OFF (MANUAL).
4. Press the RETURN soft key.
4.4.2 Selecting display range
Press the [RANGE +] or [RANGE -] key to select a range. The default ranges in
feet, meters, fathoms and passi/braza are as below. Note that range cannot be
changed in the automatic sounder mode.
Default sounder ranges
Range 1 Range 2 Range 3 Range 4 Range 5 Range 6 Range 7 Range 8
15 ft 30 ft 60 ft 120 ft 200 ft 400 ft 1000 ft 1200 ft 1500 ft
5 m 10 m 20 m 40 m 80 m 150 m 300 m 4000 m 4500 m
3 fa 5 fa 10 fa 20 fa 40 fa 80 fa 150 fa 650 fa 900 fa
3 PB 5 PB 10 PB 30 PB 50 PB 100 PB 200 PB 700 P/B 900 P/B
4.4.3 Adjusting the gain
Normally, set the gain to the point where excessive noise does not appear on
screen. Use a higher gain setting for greater depths and a lower setting for
shallow waters.
Gain too high Gain proper Gain too low
Examples of proper and improper gain