3.2 Heading Alignment
You have mounted the antenna unit facing straight ahead in the direction of the bow. Therefore, a small but conspicuous target dead ahead visually should appear on the heading line (zero degrees). In practice, you will probably observe some small bearing error on the display because of the difficulty in achieving accurate initial positioning of the antenna unit. The following adjust- ment will compensate for this error.
Correct bearing | α |
relative to heading |
|
α
Target
Antenna mounted error to port (HDG SW advance)
340 | 350 | 000 | 010 | 020 |
|
330 |
|
|
| 030 |
|
320 |
|
|
| 040 |
|
310 |
|
|
| 050 |
|
300 |
|
|
| 060 |
|
290 |
|
|
| 070 |
|
280 |
|
|
| 080 |
|
270 |
|
|
| 090 | Apparent |
260 |
|
|
| 100 | |
250 |
|
|
| 110 | position |
|
|
|
|
| |
240 |
|
|
| 120 | of target |
|
|
|
| ||
230 |
|
|
| 130 | |
220 |
|
|
| 140 |
|
210 |
|
|
| 150 |
|
200 | 190 | 180 | 170 | 160 |
|
Picture appears deviated clockwise.
Apparent position | β |
of target |
|
β | Target | 340 | 350 | 000 | 010 | 020 |
|
|
| 330 |
|
|
| 030 |
|
|
| 320 |
|
|
| 040 |
|
|
| 310 |
|
|
| 050 |
|
|
| 300 |
|
|
| 060 |
|
|
| 290 |
|
|
| 070 |
|
|
| 280 |
|
|
| 080 |
|
|
| 270 |
|
|
| 090 | Correct |
|
| 260 |
|
|
| 100 | |
|
| 250 |
|
|
| 110 | bearing |
|
| 230 |
|
|
| 130 | relative to |
|
| 240 |
|
|
| 120 |
|
|
| 210 |
|
|
| 150 | heading |
|
| 220 |
|
|
| 140 |
|
|
| 200 | 190 | 180 | 170 | 160 |
|
Antenna mounted error | Picture appears |
to starboard (HDG | deviated counterclockwise. |
SW delayed) |
|
Heading alignment
1.Select a stationary target echo at a range between 0.125 and 0.25 nm, preferably near the heading line.
2.Operate the EBL control to bisect the target echo:
a)Roll the trackball to place the arrow in the EBL1 or EBL2 box (at bottom left corner), whichever EBL you want to use.
b)Push the left button to turn on the EBL.
c)Push the left button again to send the cursor inside the effective display area.
d)Roll the trackball (coarse adjustment) or spin the thumbwheel (fine adjustment) to bisect the target with the EBL.
3.Read the target bearing.
4.Measure the bearing of the stationary target on the navigation chart and calculate the difference between actual bearing and apparent bearing on the radar screen.
5.
