Garmin 160 BLUE Manuale Utente

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On the Water
On the Water
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Understanding Sonar
If you are unfamiliar with sonar, or need help determining what is 
displayed on the chart, then this section may be for you.  This section 
is intended to help the novice user gain some understanding of how the 
Fishfinder 160 Blue operates and how it can help improve their fishing 
productivity.
To understand what the unit is displaying, it is important to have a 
general knowledge of how the unit works and how it determines what to 
display.  Briefly described, the unit operates by transmitting 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 unit to be processed and displayed on the chart.  Underwater 
data is displayed on the chart in the order that the reflected sound waves 
are received.  The diagram in the sidebar demonstrates this, showing an 
underwater scene as it would be displayed on the chart. Generally speaking, 
if the only thing between the transducer and a flat bottom is water, the 
first strong return will come from the bottom directly below the transducer, 
this return will set the bottom level.  Weaker secondary returns provide 
the detailed data.  Stronger returns will display in darker colors, with black 
being the strongest return. In Examples 1 and 2 (page 32), you can see 
that the branches and the fish were the strongest secondary returns and are 
indicated in black on the display.
That is a brief description of how your Fishfinder operates. Let’s take a 
look at how this data can help you to improve your fishing.
Unit Operation and the Chart
This fi sh is currently in a Dead Zone and is not detected 
by the sonar.  The fi sh is in the coverage area of the 
transducer, but remember the fi rst strong return sets the 
bottom level. The fi sh will never be detected since the 
bottom level will never be set below the fi sh.  The fi sh on 
the right side of the display (shown in light grey) will be 
detected and displayed when the transducer cone passes 
over the fi sh. 
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