2.11Erasing the Heading Line, North Mark
The heading line or north mark (available with gyrocompass connection) may occasionally mask a target. To view the target, you can tem- porarily erase the heading line and north mark by pressing and holding down the [GAIN (HM OFF)] control. Release the control to
Heading line
North mark
Figure 2-6 Heading line and north mark
2.12 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).
By range ring
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.
By cursor
Operate the omnipad 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.
By VRM
1.Press the [EBL/VRM SELECT] key to cir- cumscribe a VRM readout (at the bottom
EBL | VRM |
345.6°R | 5.3°NM |
23.0°R | 12.5°NM |
Figure 2-7 Display bottom, showing location
of EBL and VRM readouts
2.Press the [EBL/VRM CONTROL] key to enable control of the VRM by the omnipad.
3.Operate the omnipad to place the outside edge of the VRM on the inside edge of the target.
4.Check the VRM readout at the bottom right- hand corner of the display to find the range to the target.
5.To anchor the VRM, press the [EBL/VRM CONTROL] key.
To erase the VRM, press and hold down the [EBL/VRM CONTROL] key about two sec- onds.
Range
6.0 NM
Range ring 
2.0 interval
Target | VRM1 |
Cursor
VRM2
|
|
|
| VRM1 |
|
| VRM |
| range |
Cursor range |
| 4.0 NM |
|
|
| 4.0 NM 3.0 NM |
| VRM2 | |
|
| |||
|
|
|
| range |
Figure 2-8 Measuring range by the cursor,
range rings 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.
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