NorthStar 972, Quickstart Manual And Reference Manual

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Reference section 6 — Radar
How radar works Reference Manual Revision B
How radar works
The word “radar” is an acronym for “Radio
Detecting and Ranging.” A radio trans-
mitter sends out a very short microwave
pulse, and then a receiver listens for that
signal’s echo when it’s bounced back from
a target in its path. Targets, which may be
other boats or ships, navigational markers,
flocks of birds, or land masses, are
displayed on the 972’s screen. By knowing how long it takes for a signal to return, the
distance to a target can be determined. As
the radar antenna scans through a
360-degree rotation, it shows the target’s
location relative to your position. By
watching repeated scans of a target, such
as another vessel, you can see how that
target is moving.
Turning the radar transmitter on and off
Each time you turn on the Northstar 972,
the radar transmitter must be turned on
separately, as a safety feature.
To turn the transmitter on or off:
1. Press RADAR to display the radar screen.
2. Press
Transmit
so it indicates
On
or
Standby
, as desired.
Displaying radar
The radar image includes:
•
a compass rose to show the direction of
true or magnetic north
•
a gray heading line. This line indicates
your heading, not
Course-Over-Ground, and can be used
to compare the radar presentation with
the view in front of the vessel.
•
in the upper left corner, the transmit
status (
Transmit on
or
Transmit standby
),
and the current radar scale (
Range
indicates the distance from the center
to the largest range ring, and
RR
indicates the spacing between the
range rings)
•
in the upper right corner, pulse length,
speed setting, rotation mode and Main
Bang Suppression (MBS)