Intermec PRO 128 manual What YOU see on Screen, Thermoclines. Thermoclines are sharp

USING THE TRACKER UNIT

WHAT YOU SEE ON SCREEN

moving up and down over flat bottom, the bottom depiction often appears in regular variations that match wave timing.

Structure. Structure is defined as any object physically attached to the bot- tom. The sonar configuration of the Tracker unit is optimized to give the most accurate depiction of bottom structure possible. Grass, trees, stumps, wrecks or other debris are accurately displayed, however the depiction of these objects varies with boat speed and direction. The best way to learn to interpret structure is to operate the Tracker unit over a variety of known con- ditions and experiment with user functions to best represent those condi- tions on-screen.

Surface Clutter. Surface clutter is the layer of water near the surface that is rich in algae and other growth, and often is aerated by wind or wave action. This area of water interferes with sonar transmission and often appears on-screen as regular clusters of individual dots near the “0” line.

Thermoclines. Thermoclines are sharp	Thermocline Second Return
differences in water temperature.
These are easily identified by the con-
tinuous nature of the return.
Second Returns. When a sonar signal
is reflected off the bottom back to the
transducer, there is often enough ener-
gy left in the signal to be reflected off
the surface of the water back to the
bottom a second time. Second returns
appear as a slightly weaker bottom
representation exactly twice the depth
of the primary bottom return. The sec-
ond return is most likely to occur in
shallow water and in areas of relatively
hard bottom.

Fish ID. The Tracker unit uses advanced signal processing to further evalu- ate any sonar return between the surface and the bottom. For instance, a small school of bait fish usually appears as a dense cluster of individual dots. If the return meets certain additional criteria, a fish symbol will be assigned.

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