Furuno 1761 MARK-3 - Manual (Page 17)

2-6
2. Position the EBL so it bisects the target
by operating the trackball.
3. Press the [EBL] key again to fix the EBL
to the position.
4. Check the bearing readout to find the
bearing of the target. To erase the EBL,
press and hold down the [EBL] key for
about three seconds.
6.0 NM
2.0
EBL1 bearing
R: Relative Bearing
T: True Bearing*
40.0° R
EBL
EBL
Target
Cursor
Cursor Bearing
R: Relative Bearing
T: True Bearing*
41.5°R
4.0 NM
MAG115.0°
MAG (or GYRO) BEARING*
*: Heading sensor
(or gyrocompass)
connection required
Figure 2-6 Measuring Bearing by the EBL
and Cursor
The bearing measured by the cursor or the
EBL can be displayed in relative or true bear-
ings (heading sensor or gyrocompass con-
nection required). Relative bearings are
relative to the bow of the vessel, and true
bearings are relative to the True North. The
indication “MAG” (or GYRO”) and the head-
ing sensor (or gyrocompass) bearing (your
ship’s bearing) appear at the top of the
screen.
Note that the bearing to the cursor always
varies with trackball operation. The EBL and
its indication, however, are automatically fixed
when the [EBL] key is pressed or 10 seconds
elapses without trackball operation.
Tips on measuring bearing
• Bearing measurements of smaller targets
pips are more accurate; the center of
larger target pips is not as easily identi-
fied.
• Bearings of stationary or slower moving
targets are more accurate than bearings
of faster moving targets.
• To minimize bearing errors keep echoes
in the outer half of the picture by chang-
ing the range scale; angular difference
becomes difficult to resolve as a target
approaches the center of the display.
2.17 Shifting and Zooming the
Display
The [SHIFT/ZOOM] key has two functions:
display shifting and display zoom. Each time
the key is pressed the function changes in
the following sequence.
Normal Shift Zoom
Figure 2-7 SHIFT/ZOOM key sequence
Shift
The own ship’s position can be shifted to any
position within the current range. The primary
advantage of the shifted display is that for
any range setting, the view ahead of your own
ship can be extended without changing the
range.
Place the cursor on area you wish to shift to
the screen center and then press the [SHIFT/
ZOOM] key. The indication “SHIFT” appears.
To restore normal operation press the key
twice.
Note: If the cursor is not within the current
range when the key is pressed, an audible
beep sounds and the outermost range ring
blinks twice , even if the range rings are
off.
Zoom
The zoom feature allows you to double the
area between own ship and an arbitrary lo-
cation, to take a closer look at an area of in-
terest without changing the range.
1. Operate the trackball to place the cursor
on the target you want or area you want
to zoom.