What YOU see on Screen

USING THE TRACKER UNIT

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.