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E-Series Networked Display Reference Manual
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 range (normally
below 3 nm) and with large 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.
Multiple echoes
Multiple echoes are uncommon but can occur if there is a large object with a wide
vertical surface at a comparatively short range. The transmitted signal bounces
between the object and your own vessel, producing multiple echoes. The false
True echo
Side echoes
Main lobe
Antenna
Arc
Side
lobe
Side
lobe
D1638-4
False echo
Passing
ship
True echo
D1641-4
True echo
False echo
Mast
or funnel
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