Furuno FR-7112 - Manual (Page 19)

2-7
2.14 Measuring the Range
You can measure the range to a target three
ways: by the range rings, by the cursor, and by
the VRM (Variable Range Marker).
Measuring range by range rings
Count the number of rings between the center
of the display and the target. Check the range
ring interval and judge the distance of the echo
from the inner edge of the nearest ring.
To turn the rings on or off, see the menu opera-
tion later (Chapter 3).
Measuring range by cursor
Operate the trackball to place the cursor inter-
section on the inside edge of the target echo,
The range to the target, as well as the bearing,
appears at the bottom of the display.
Measuring by VRM
1. Press either [VRM 1] or [VRM 2] key. The
readout of the active marker is circum-
scribed.
EBL
345.6
°
R
23.0
°
R
VRM
5.3 NM
12.5 NM
Figure 2-8 Display bottom, showing location
of EBL and VRM readouts
2. Operate the trackball to place the outside
edge of the VRM on the inside edge of the
target. The trackball must be operated within
five seconds after pressing a [VRM] key, oth-
erwise the corresponding VRM cannot be
operated. Press the [VRM] key again to ad-
just the VRM.
3. Check the VRM readout at the bottom right-
hand corner of the display to find the range
to the target.
4. To anchor the VRM, press the [VRM] key
again.
To erase the VRM, press and hold down the
corresponding [VRM] key about two seconds.
VRM1
VRM2
6.0 NM
2.0
Range
Range ring
interval
Target
Cursor
Cursor range 4.0 NM
VRM
4.0 NM
3.0 NM
VRM1
range
VRM2
range
Figure 2-9 Measuring range by the cursor
and VRM
Note: You can display the range readout of
the VRM and cursor in nautical miles,
statute miles or kilometers. For details
see the next chapter.
2.15 Measuring the Bearing
There are two ways to measure the bearing to a
target: by the cursor, and by the EBL (Electronic
Bearing Line).
Measuring bearing by cursor
Operate the trackball to bisect the target with
the cursor intersection. The bearing to the tar-
get appears at the bottom of the display.
Measuring by EBL
1. Press the [EBL 1] or [EBL 2] key.
2. Operate the trackball to bisect the target with
the EBL.
The trackball must be operated within five
seconds after pressing an [EBL] key, other-
wise the corresponding EBL cannot be oper-
ated. Press the [EBL] key again to adjust the
EBL.
3. Check the EBL readout at the bottom left-
hand corner of the display to find the bear-
ing to the target.
4. To anchor the EBL, press the corresponding
[EBL] key again.
To erase the EBL and its readout, press and hold
down the corresponding [EBL] key about two
seconds.