5
C. False echoes caused by side lobe
The radiant beam emitted from an antenna contains side lobes in directions other
than that of the main beam. Since the side lobe level is low, it in no way affects distant
targets. However, if there is a strong reflecting target near the ship, it sometimes ap-
pear as a circular-arc false echo on the screen.
When located near large targets such as land, the
ship's mast, etc. sometimes appears as a false
echo of circular-arc shape.
3
1
HU
Real echo
Multiple
echoes
Fig.2-6 False echoes of radar (Multiple echoes)
3
1
HU
Antenna
Main beam
Side lobes
Real echo
False sidelobe
echoes
Fig.2-7 False echoes of radar (Caused by side lobe)
CAUTION
!
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