3-3
8. Press a [RANGE] key to bisect the target
with the heading marker. See Figure 4-5
(b).
9. Press the [MENU] or select menu by the
trackball to complete the adjustment.
10.As a final test, move the boat towards a
small buoy and confirm that the buoy
shows up dead ahead on the radar when
it is visually dead ahead.
Heading Marker
Target
Tuning Range
Markers
Heading
Marker
(dotted line)
Figure 3-5 Display during Heading
adjustment
3.4
MAG or GYRO Indication
When a gyrocompass or heading sensor is
connected to this radar, select it on the IN-
STALLATION menu.
1. Select “3. MAG/GYRO” on the INSTAL-
LATION menu.
2. Select “MAG” (factory setting) or “GYRO”
with the [RANGE] key.
3. Press the [MENU] key to complete the
setting.
3.5 Range Unit Selection
The range unit of the cursor and the VRM is
selectable for either “NM” (nautical mile) or
“KM” (kilometer).
1. Select “4. NM/KM” on the INSTALLATION
menu.
2. Select “KM” (factory setting) or “KM” with
the [RANGE] key.
3. Press the [MENU] key to complete the
setting.
3.6 Measurement of Blind
Shadow Sectors
In some shadow sectors, it should be remem-
bered that there may not be sufficient inten-
sity to obtain an echo from very small targets
even at close range, despite the fact that a
large vessel may be detected at a much
greater range in non-shadowed sectors. For
these reasons the angular width and relative
bearing of any shadow sectors should be
done during sea trails. In other ships it should
be done at the first opportunity after fitting a
new radar set.
It should be understood that even a small
shadow sector can hide another vessel if it is
on a collision course. The bearing will remain
constant in the shadow area and the ap-
proach of the other vessel may remain un-
detected until it is too late to avoid a
dangerous situation.
There are two methods of determining the
angular width of a shadow sector.
1. Turn the boat very slowly through 360
degrees while a small but clearly defined
target is observed at a distance of a mile
or so. (Do not use a buoy with a reflector
as this target is too powerful to achieve
the required result.)
