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5.6 Entering Initial Settings
1) At the Installation Setup 1 menu, press the
cursor pad to select Key Beep. (Key Beep
turns on or off the buzzer which sounds when
a key is pressed.)
2) Press the cursor pad to select OFF or ON.
3) Select Hdg Sensor.
4) Select type of heading sensor connected to
the radar; MAGnetic compass or
GYROcompass.
5) Press the [ENT] key.
6) Select ANTENNA UNIT.
7) Select M841 when using M841 antenna unit.
Leave the menu open to complete the next
several adjustments.
5.7 Relative Bearing 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
mark (zero degrees).
In practice, you will probably observe some
small error on the display because of the dif-
ficulty in achieving accurate initial position-
ing of the antenna unit. The following
adjustment will compensate for this error, up
to ±30 degrees.
1) Identify a suitable target (for example, ship
or buoy) at a range between 1/8 to 1/4 miles,
preferably near the heading mark. To mini-
mize error, keep echoes in the outer half of
the picture by changing the range.
2) Display the Installation Setup 2 menu.
● INSTALLATION SETUP 2 ●
Select item and option
by trackball.
1. Align Heading
2. Adjust Sweep Timing
3. On Hours 000019.8 H
4. Tx Hours 000016.0 H
. . . . . . . . . . . . . . . . .
Press HM-OFF to temporarily
hide menu.
<Press MENU for main menu.>
Figure 5-18 Installation setup 2 menu
3) Select Align Heading and press the [ENT]
key.
4) Press the cursor pad to bisect the target se-
lected at step 2 with the EBL.
5) Press the [ENT] key,
6) As a final test, move the boat towards a small
buoy and confirm that the buoy shows up
dead ahead on the radar when it is visually
dead ahead.
5.8 Sweep Timing
This adjustment ensures proper radar perfor-
mance, especially on short ranges. The radar
measures the time required for a transmitted
echo to travel to the target and return to the
source. The received echo appears on the dis-
play based on this time. Thus, at the instant
the transmitter is fired, the sweep should start
from the center of the display (sometimes
called sweep origin.)
A trigger pulse generated in the display unit
goes to the antenna unit through the signal
cable to trigger the transmitter (magnetron).
The time taken by the signal to travel up to
the antenna unit varies, depending largely on
the length of signal cable. During this period
the display unit should wait before starting
the sweep. When the display unit is not ad-
justed correctly, the echoes from a straight
local object (for example, a harbor wall or
straight pier) will not appear with straight
edges—namely, they will be seen as “pushed
out” or “pulled in” near the picture center. The
range of objects will also be incorrectly
shown.
(1) Correct
(2) Target pushed
inward
(3) Target pushed
outward
Figure 5-19 Examples of improper and
correct sweep timings