2. RADAR, CHART RADAR OPERATION
2-14
2.13 How to Suppress Second-trace Echoes
In certain situations, echoes from very distance targets may appear as false echoes
(second-trace echoes) on the screen. This occurs when the return echo is received
one transmission cycle later, or after a next radar pulse has been transmitted.
This equipment lengthens the pulse repetition period to reject the false echoes.
Note: This function decreases the number of echoes hits. Carefully use this function
so that the possibility of detecting small targets and high-speed craft does not lessen.
To reject second-trace echoes, open the [1 ECHO] menu then set [5 2ND ECHO REJ]
(B type) or [4 2ND ECHO REJ] (IMO and A types) to [ON] then close the menu.
2.14 Presentation Modes
This radar has the following orientation modes in the radar mode:
2.14.1 Orientation modes
This radar has the following orientation modes in the radar mode:
Relative Motion (RM)
Head-up: Unstabilized.
STAB H UP: Head-up with compass-stabilized bearing scale (True Bearing) where
the bearing scale rotates with the compass reading.
Course-up: Compass-stabilized relative to ship's orientation at the time of selecting
course-up.
North-up: Compass-stabilized with reference to North.
Stern-up: Unstabilized.
Pulse
interval
Actual ranges
Second-trace
echo
Measured ranges