1.18 Measuring the Range
Measuring range by the fixed range rings
Use the fixed range rings to obtain a rough estimate of the range to a target. They are concentric solid circles about own ship, or the sweep origin. The number of rings is auto- matically determined by the selected range scale and their interval is displayed at the
0.55NM
15.0°R
Range and bearing to cursor
Target
Ring interval
| Cursor |
| No. 1 VRM |
| (dotted) |
| No. 2 VRM |
| (dashed) |
Active marker is | VRM |
0.375NM | |
circumscribed. | 0.550NM |
| Range to |
| Range to No. 1 VRM |
| No. 2 VRM |
Measuring range by the variable range marker (VRM)
Use the Variable Range Markers (VRMs) for more accurate measurement of the range to a target. There are two VRMs, No.1 and No.2, which appear as dashed rings so that you can discriminate them from the fixed range rings. The two VRMs can be distinguished from each other by different lengths of dashes.
1.Press the [VRM ON] key to display either of the VRMs. Successive presses of the [VRM ON] key toggle the active VRM between No.1 and No.2 and the currently active VRM readout is circumscribed.
2.Rotate the VRM rotary control clockwise or counterclockwise to align the active VRM with the inner edge of the target of interest and read its distance (unit: nm) at the
3.Press the [VRM OFF] key to erase each VRM.
Figure 1-15 How to measure
range by VRM
1.19 Measuring Bearing
Use the Electronic Bearing Lines (EBLs) to find bearing of a target. There are two EBLs, No.1 and No.2, which are toggled by suc- cessive presses of the [EBL ON] key. Each EBL is a straight dashed line extending out from the own ship position up to the circum- ference of the radar picture. The fine dashed line is the No.1 EBL and the coarse dashed one is the No.2 EBL.
1.Press the [EBL ON] key to display either of the EBLs. Successive presses of the [EBL ON] key toggle the active EBL be- tween No.1, No.2 and index lines (if dis- played) and the currently active EBL readout is circumscribed.
2.Rotate the EBL rotary control clockwise or counterclockwise until the active EBL bisects the target of interest, and read its bearing at the
3.Press the [EBL OFF] key to erase each EBL.
The EBL readout is affixed by “R” (relative) if it is relative to own ship’s heading, or “T” (true) if it is referenced to the North, as determined by the item EBL/VRM on the OTHER menu.