Furuno FAR-2157-D, FAR-2157-BB installation manual Heading Alignment, Heading alignment

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.Left-click the MENU box at the right side of the screen to close the menu.

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