Furuno NAVNET 1752C - Manual (Page 51)

2. RADAR OPERATION
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2.12 Erasing the Heading Line, North Marker
The heading line indicates the ship's heading in all presentation modes. The
heading line is a line from the own ship position to the outer edge of the radar
display area and appears at zero degrees on the bearing scale in head-up
mode; it changes its orientation depending on the ship orientation in north-up,
course-up and true motion modes.
The north marker appears as a short dashed line. In the head-up and course-up
modes the north marker moves around the bearing scale as the ship’s heading
moves.
To temporarily erase the heading line and north marker, press the RADAR
DISPLY soft key followed by the HL OFF soft key. Release the key to redisplay
the markers.
2.13 Reducing Noise
Noise, appearing on the displays as random “speckles,” can be reduced as
follows:
1. Press the [MENU] key to open the menu.
2. Press the RADAR DISPLAY SETUP soft key.
3. Select NOISE REJECTION and press the EDIT soft key.
4. Select OFF, HIGH or LOW as appropriate.
5. Press the ENTER soft key or the [ENTER] knob.
6. Press the [MENU] key to close the menu.