Garmin 496 Manuale Proprietario

The transducer mounted on your vessel transmits sound waves 

toward the bottom of a lake, stream, or seabed in a cone-shaped 

pattern. When a transmitted sound wave strikes an underwater 

object—such as the bottom, a piece of structure, or a fish—sound is 

reflected back to the transducer. The transducer collects the reflected 

sound waves and sends the data to the GPSMAP 496 to be processed 

and shown. The underwater data is shown on the Sonar screen in the 

order that it is returned: first returned is the first on the screen. 

Generally speaking, if the only thing between the transducer and 

the bottom is water, the first strong return comes from the bottom 

directly below the transducer and sets the bottom level. Weaker 

secondary returns provide the detailed data. Stronger returns screen 

in darker colors, with red being the strongest return.

One of the first things to understand about sonar is that the 

transducer sends a beam down to the bottom of the water, much like 

the beam of a flashlight. The beam starts small near your vessel and 

expands as it gets to the bottom. Refer to “Transducer Coverage” for 

more detailed information.
The Sonar Page does not show a three-dimensional representation of 

the underwater environment; the screen is in two-dimensions, much 

like if you took a picture of an aquarium. Only the depth of the item 

in the water is shown. The Sonar Page does not show you where an 

item is located horizontally in the water, as shown in the drawings 

below. The fish is not directly above the tree in reality, but it can 

look like it is on the Sonar Page.

20'

10'

1'

GPSMAP 496 Owner’s Manual 

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