Furuno NATVET 1824C - Manual (Page 40)

2. RADAR OPERATION
2-11
2.12 Erasing the Heading Line, North Marker
The heading line indicates the ship's heading in all presentation modes. It 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 in the north-up, course-up
and true motion modes with ship’s movement.
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. (If the radar soft
keys are not shown, hit the
CLEAR key to display them.)
2.13 Reducing Noise Interference
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, then press the EDIT soft key.
4. Select OFF, LOW or HIGH as appropriate.
5. Press the ENTER soft key.
6. Press the
MENU key to close the menu.
2.14 Rejecting Radar Interference
Radar interference may occur when near another shipborne radar that is operating in the
same frequency band as your radar. Its on-screen appearance looks like many bright dots
either scattered at random or in the form of dotted lines extending from the center to the
edge of the display. Interference effects are distinguishable from normal echoes because
they do not appear in the same place on successive rotations of the scanner.
Be sure to turn off the interference rejector when no interference exists – weak targets may
be missed.
Radar interference