Eagle Electronics 640C Fish Finder User Manual


 
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depth appears in a box at the right end of the cursor line. To clear the
cursor, press
EXIT.
9. If you are drifting at a very low speed or anchored, you are not mov-
ing fast enough for a fish to return the tell-tale fish arch signal. As you
drift over a fish, or as a fish swims through the transducer's signal
cone, the fish echo will appear as a straight line suspended between the
surface and the bottom.
10. To turn off the unit, press and hold
PWR key for three seconds.
Sonar Operations
As you can see from the quick reference, basic operation of this fish
finder is pretty easy right out of the box. If you are a sonar novice, try
operating the unit with the factory defaults until you get a feel for how
it's working.
As you are learning the basics, there is one setting you might want to
tinker with from time to time — Sensitivity.
Sensitivity controls the unit's ability to pick up echoes. If you want to
see more detail try increasing the sensitivity a little at a time. There
are situations when too much clutter appears on the screen. Decreasing
the sensitivity can reduce the clutter and show the strongest fish ech-
oes if fish are present. As you change the sensitivity setting you can see
the difference on the chart as it scrolls.