The capability of a radar varies depending on where the radar is mounted, the
radars performance, weather conditions, and the skill of the operator. This chapter
describes the conditions that affect the capability of the radar, and the correct
interpretation of the radar picture.
How to Interpret the Radar Picture
To interpret the radar picture, an operator should be familiar with the radar video
presentation caused by the wanted and unwanted effects. For instance, the
produced by bridges, sand beaches, waves and even a boat’s wake may all be
represented differently than expected based on their visual appearance.
For correct interpretation of the radar picture, it is highly recommended that the
operator practice using the radar in good weather conditions.
Normal Echoes
The figure above shows an example of typical radar picture compared against a
sample real-world scenario. There are a number of things to learn from this image
regarding how a radar works. Here is a list of some important ones:
1. The bouy #1 is being blocked by the cape or hill and is not visible in the radar
window.
2. Due to its proximity and size, the large boat returns a strong radar return that
is similar to its actual profile. On the other hand, the small boat is painted as
a small dot, because its reflection area is smaller. Also notice that the smaller
boats wake returns a large reflection.
3. The hill on the starboard side of the vessel, because of its dense forest and hilly
nature, returns large echoes, while the sandy beach to the port returns a weak
radar image. The exception to the port side return is the windbreak forest which
returns strong echoes because of its profile differences.
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Understanding Radar
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