3-1
3. ADJUSTMENTS
3.2 Sweep Timing
This adjustment ensures proper radar per-
formance, especially on short ranges. The
radar measures the time required for a trans-
mitted echo to travel to the target and return
to the source. The received echo appears on
the CRT based on this time. Thus, at the in-
stant the transmitter is fired, the “Sweep
should start from the center of the CRT
(sometimes called sweep origin.)
A “trigger” pulse generated in the display unit
goes to the scanner unit through the inter-
connection cable to trigger the transmitter
(magnetron). The time taken by the signal to
travel up to the scanner unit varies, depend-
ing largely on the length of interconnection
cable. During this period the display unit
should wait before starting the sweep. When
the display unit is not adjusted correctly, the
echoes from a straight local object (for ex-
ample, 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 3-1 Examples of Improper and
correct Sweep timings
1. Transmit the radar on the shortest range
and adjust the [GAIN] and [A/C SEA] con-
trols.
2. Visually select a straight echo (harbor
wall, straight pier).
3. Press and hold down the [MENU] key
(about 10 seconds) until the INSTALLA-
TION menu appears.
After checking the unit for proper installation
its time to adjust it.
WARNING
Before transmitting the radar make sure
no one is near the scanner unit, to pre-
vent the potential risk of being struck
by the rotating scanner and exposure
to RF radiation hazard.
3.1 Preparation
1. Press the [POWER] key on the display
unit, and the front panel will light up. In
approximately two minutes and 30 sec-
onds, the message “ST-BY” will appear
at center of the screen. While this warmup
is in process, set the [GAIN] control at two
o’clock, and the [A/C RAIN] and [A/C SEA]
controls at fully counterclockwise.
2. When “ST-BY” appears press the [TX]
key.
3. Bring up the [GAIN] control until a small
amount of noise appears on the screen.
4. Adjust the [GAIN] control on the front
panel, for a little background noise show-
ing on the screen, and then hit the [Range
-] key several times to bring you down to
the minimum range. Without disturbing
the front panel [GAIN] control, adjust the
[A/C SEA] control until nearby radar tar-
gets are clearly shown on the screen. Too
much A/C SEA action will eliminate small
targets, and too little A/C SEA action will
cause the screen to be so full of targets
and noise that it is hard to determine
which target is which as compared to vi-
sual sightings. Note that adjusting the
[GAIN] and [A/C SEA] controls in this
manner (GAIN at long range, A/C SEA at
short range) will equalize the picture at
all ranges, and you will not have to jockey
back and forth with the [GAIN] control
especially when you change range scale.
