What's On The Sonar Display - Humminbird ] 981 Installation & Operation Manual

98x_Manual_531376-1_A.qxd 2/23/2005

WHAT'S ON THE SONAR DISPLAY

The 900 Series™ can display a variety of useful information about the area under and adjacent to your boat, including the following items:
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1 Depth - water depth; can be set to alarm when the water becomes too shallow.
2 Timer - Elapsed time with Speed accessory or GPS Receiver.
3 Distance - Distance traveled with Speed accessory or GPS Receiver.
4 Average Speed - Average speed reading with Speed accessory or GPS Receiver.
11:40 AM Page 30
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Barometric Pressure - Requires optional-purchase WeatherSense®
Temperature - water surface temperature
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Speed - if a Speed accessory or GPS
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Receiver is attached, the 900 Series™
can display the speed of the boat,
and can keep a triplog of nautical or
statute miles traveled.
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Thermoclines - layers of water with
different temperatures that appear
at different depths and different
times of the year. A thermocline
typically appears as a continuous
9 band of many colors moving across
the display at the same depth.
9 Sonar Color Bar - color spectrum
indicating low to high sonar intensity
returns, where red indicates high
intensity and white indicates low
intensity.
10 Bait Ball
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RTS® (Real Time Sonar) Window
12 Second Sonar Return - when the
sonar signal bounces between the
bottom and the surface of the water
and back again. Use the appearance
of the second return to determine
bottom hardness. Hard bottoms will
show a strong second return, while
soft bottoms will show a very weak
one or none at all.