Antenna height | Target height | Maximum range |
(meters) | (meters) | (Nautical miles) |
5 | 10 | 12 |
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Radar image quality
A number of factors can affect the quality of a radar image, including echoes, sea clutter, and other interference.
Not all radar echoes are produced by valid targets. Spurious echoes may be caused by:
•Side lobes.
•Indirect echoes.
•Multiple echoes.
•Blind sectors.
•Sea, rain, or snow clutter.
•Interference.
Through observation, practice, and experience, you can generally detect these conditions very quickly and use the radar controls to minimize them.
Side Lobes
Side lobe patterns are produced by small amounts of energy from the transmitted pulses that are radiated outside the narrow main beam. The effects of side lobes are most noticeable with targets at short ranges (normally below 3 nm), and in particular with larger objects. Side lobe echoes form either arcs on the radar screen similar to range rings, or a series of echoes forming a broken arc.
Indirect Echoes
There are several types of indirect echoes or ghost images. These sometimes have the appearance of true echoes, but in general they are intermittent and poorly defined.
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