1. OPERATIONAL OVERVIEW
1-11
1.9
Choosing a Pulse Length
The pulse length in use appears at the top left position on the screen. Appropriate pulse lengths
are preset to individual range scales and functions keys. If you are not satisfied with the pulse
length setting on the 1.5 nm or 3 nm range, you may change it as below.
1. Press the
MENU
key to open the menu.
2. Use the trackball to choose the Echo menu and then press the
ENTER
key.
3. Use the trackball to choose Pulse Length and then press the
ENTER
key.
4. Choose Short or Long as appropriate and then press the
ENTER
key.
5. Press the
MENU
key to close the menu.
1.10
Adjusting the Gain (sensitivity)
The
GAIN
control adjusts the sensitivity of the receiver. The proper setting is such that the back-
ground noise is just visible on the screen. If you set up for too little sensitivity, weak echoes may
be missed. On the other hand excessive sensitivity yields too much background noise; strong tar-
gets may be missed because of the poor contrast between desired echoes and the background
noise on the display.
1.10.1
Choosing gain adjustment method
Gain may be adjusted automatically or manually. Push the
GAIN
control to choose automatic or
manual adjustment alternately. The adjustment method currently chosen is show at the top right
corner of the screen. In the example below the adjustment method is “AUTO”.
Gain adjustment method indicator
1.10.2
Automatic gain adjustment
1. Press the
MENU
key to open the menu.
2. Choose the Echo menumenu and then press the
ENTER
key.
3. Choose Auto Gain and then press the
ENTER
key.
4. Choose the sea condition which best matches the auto gain options.
5. Press the
ENTER
key followed by the
MENU
key to close the menu.
Short
Long
TUNE MANL
GAIN AUTO
SEA MANL
RAIN AUTO
Gain adjustment method (AUTO)
Rough
Moderate
Calm