Furuno GD-280, Operator'S Manual

Page: 171 / 280

11-7
2. Press the [3] key to display the Echo Signal menu.
3. Press
[↑]
or
[↓]
to select Interference Rejection.
4. Press
[←]
or
[→]
to select level of interference rejection desired. The higher the number the
greater the degree of suppression. Select Off when no interference exists, so as not to miss
weak targets.
5. Press the [MENU] key several times to close the menu.
The indication IR1, IR2 or IR3 appears at the top right corner on the screen when the
interference rejector is active.
11.3.6 Echo averaging
The echo average feature effectively suppresses sea clutter. Echoes received from stable
targets such as ships appear on the screen at almost the same position every rotation of the
antenna. On the other hand, unstable echoes such as sea clutter appear at random positions.
To distinguish real target echoes from sea clutter, this radar performs scan-to-scan correlation.
Correlation is made by storing and averaging echo signals over successive picture frames. If an
echo is solid and stable, it is presented in its normal intensity. Sea clutter is averaged over
successive scans resulting in the reduced brilliance, making it easier to discriminate real targets
from sea clutter.
To properly use the echo average function, it is recommended to first suppress sea clutter with
the [A/C SEA] control and then do the following:
1. Press [MENU], [9], [3], [3] to display the Echo Signal menu.
2. Press
[↑]
or
[↓]
to select Echo Average.
[ECHO SIGNAL]

Echo Color Yellow Green Color
Clutter Sweep Off On (Link) Off (Fix)
Sweep Level 1 2 3
Echo Average Off 0.5 1 2 3
Interference Rejection Off 1 2 3
Echo Stretch Off 1 2
Echo Enhance Off On
Noise Rejection Off On
Video Contrast 1 2 3
A/D Curve A B C D

↑↓←→
: Select & Set.
MENU : Back to Main Menu. HL-OFF: Menu off temporarily.