8 BASIC RADAR THEORY
■Multiple echoes
Multiple echoes may appear when a
Own ship | Another ship |
Multiple echoes will appear beyond the target’s true echo point on the same bearing of a large target. They can be reduced with proper adjustment of the
[SEA]/[ | ] control. |
|
See p. 10 for the [SEA]/[ | ] control. | |
False echoes
True echo
■Minimum range
Detection at short range is very important. Minimum range is determined primarily by transmitter pulse length, vertical beam width and height of the scanner unit. The shorter the transmission time, the quicker the return echoes can be received and their distance mea- sured.
The ability to see targets very close to the ship is de- creased if the scanner is mounted too high off the water, because the bottom of the vertical beam of the scanner cuts off nearby targets.
Vertical beam width
This target can not be recognized with radar. Pulse length
Pulse starting point
The target in this area can not be recognized.
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