Reference Manual Part 2

135 Chapter 11: Radar
Your position
By default your boat is shown at the centre of the radar display and
your dead-ahead bearing is indicated by a vertical line known as
the Ship’s Heading Marker (SHM).
Operation modes
The radar gives excellent results in one of the four preconfigured
operation modes under the GAIN softkey. Select the mode that
best suits your circumstances: attempting to make manual adjust-
ments to the settings could degrade your image. (However, this
facility is available.)
See
page 140 for more information.
Other vessels or objects
On-screen targets may be large, small, bright or faint, depending
on the size of the object, its orientation and surface type.
Remember that the strength of an object’s echo may not be propor-
tional to the physical size of the object. For example, a nearby
object might produce an echo of the same strength as a more dis-
tant, but larger, object.
With experience, the approximate size of different objects can be
determined by the relative size and brightness of the echoes.
Factors affecting echo strength
• The physical size of the reflecting object.
• The material from which the object is made. Metallic surfaces
reflect signals better than non-metallic.
• Vertical surfaces, like cliffs, reflect the radar signal better than
sloping surfaces, like sandbanks.
• High coastlines and mountainous coastal regions can be ob-
served at longer radar ranges. Therefore, the first sight of land
may be a mountain several miles inland from the coastline. Al-
though the coastline may be much nearer, it may not appear on
the radar until the vessel is closer to shore.
• Some targets, such as buoys and small boats, can be difficult to
discern, because they do not present a consistent reflecting
surface as they bob about in the waves. Consequently, these
echoes tend to behave erratically on the radar screen.
• Buoys and small boats often resemble each other, but boats
can often be distinguished by their motion.
• Trees and shrubbery do not reflect radar. Thus, they can dis-
guise the shape of nearby land.
11.5 Using waypoints with the radar
You can use waypoints in the radar application for navigation (just
like in the chart application), using the WPTS/MOB button.
You can also edit waypoints from within the radar application.
For full details on using waypoints, see Chapter 4:Using Waypoints
on page 35 and Chapter 5:The Chart Application on page 43.