This adjustment ensures proper radar performance, 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 display 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 adjusted 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) Target | (2) Correct | (3) Target pushed |
pulled |
| outward |
Examples of improper and correct sweep timing
a)Choose ON and then press the ENTER soft key.
b)Transmit on the shortest range and confirm that gain and A/C SEA are properly adjusted.
c)Visually select a target which forms straight line (harbor wall, straight piers).
d)Rotate the ENTER knob to straighten the target selected at step b), and then press the ENTER knob to finish.
23.Choose M. B. SUPPRESSION and press the EDIT soft key.
M. B. SUPPRESSION
▲
{ON ~ OFF
▼
24.Choose ON and then press the ENTER soft key. Main bang is the “black hole” which appears at the display center on short ranges. Rotate the ENTER knob to suppress the main bang. After adjusting, press the RETURN key.
25.Choose RADAR ANTENNA HEIGHT and then press the EDIT soft key.
RADAR ANT. HEIGHT
{HIGH (>10m, 33ft)
~MEDIUM
