Garmin CR 1522, Owner'S Manual

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4.1 Multiple Echoes 61
CHAPTER 4 FALSE ECHOES
False echoes are echoes appearing at positions where there is no target. False echoes occur
occasionally as a result of the antenna receiving signals reflected off secondary objects. The
phenomenon can be reduced but it takes some experience to recognize the distinct patterns of
these echoes. There are several types of false echoes, you should familiarize yourself with the
appearances of each type of false echoes, and the situations in which each type of false echoes
tends to occur.
4.1 Multiple Echoes
When echoes are reflected from a nearby object, some of the reflected echoes may
bounce back and forth between the own ship and the nearby object, forming multiple
targets on the radar display at multiple ranges of the actual object. This effect can be
reduced by decreasing Gain or adjusting the Sea clutter reduction (see 2.4 ).
False Echoes
4.2 Side-Lobe Echoes
The radio waves emitted in the desired direction is the main lobe, while unwanted
radiation on each side of the main lobe are called side lobes. Larger objects near the own
ship may be detected by both the main lobe and the side lobes, showing duplicates at the
same range. This effect can be reduced by decreasing Gain or adjusting the Sea clutter
reduction (see 2.4 ).
False Echoes