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currently represented in the zoomed window (on the left part of the screen). It is turned On
selecting the Echo Sounder Split page.
10 A-Scope
A real time representation of fish and bottom features passing through the beam of the
transducer. It is drawn as horizontal lines whose length and hue is proportional to the sonar
strength returned. When the default palette is selected, the strongest sonar returns will
be shown as the color displayed of the top of Color Bar while the weakest as the bottom
color.
11 Operating Frequency
Readout of the selected operating frequency.
5.2.1
Understanding the Echogram display
The main elements that can be easily distinguished into an Echogram are:
1 Fishes
Fish are represented as arcs because of the cone angle of the transducer. In fact as the
boat passes over the fish the leading edge of the cone strikes the fish, causing a display
pixel to be turned on. As the boat passes over the fish, the distance to the fish decreases
turning each pixel on at a shallower depth on the display. When the boat is directly over
the fish, the first half of the arch is formed and since the fish is closer to the boat, the signal
is stronger and the arch is thicker. As the boat moves away from the fish, the distance
increases and the pixels appear at progressively deeper depths forming the remaining half
of the arch.
2 Thermoclines
Are the zones where two layers of different water temperatures meet. The greater the
temperature differential, the thicker the thermocline is shown on the screen. Thermoclines
are represented as horizontal stripes of noise. They are very important for fishing since often
many species of game fish like to suspend in, just above, or just below the thermoclines.
3 White Line
The White Line shows the difference between hard, soft bottoms and even distinguishes
between fishes and structures located near the bottom. In this way it is easier to tell the
difference between a hard and soft bottom and even to distinguish fishes and structures
located nearby the bottom. For example, a soft, muddy or weedy bottom returns a weaker
echo that is shown with a narrow white line while a hard bottom returns a strong echo that
causes a wide white bottom line.
4 Surface Clutter
Appears like noise at the top of the screen extending many feet below the surface. It's
Fig. 5.2.1 - The Fish Finder Echogram
User Manual -
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