USING THE 405SX
WHAT YOU SEE ON SCREEN
repeat the same image it is often necessary to travel the same speed and direction over the location where the structure was originally located.
The 405SX is also capable of showing layers of water having different temperatures. These temperature differences, called thermoclines, appear at different depths, depending on current conditions. A thermocline typically appears as a continuous band of light gray moving across the display at the same depth. Thermoclines always appear above the bottom.
It is important to remember that sonar cannot distinguish between a fish and some other object suspended in the water. Regardless of the object the sonar detects, each will be drawn as an arch.
Fish ID. The 405SX uses
advanced signal processing to further evaluate 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.
There are three different size fish symbols used to
indicate the intensity of the sonar return. While signal
intensity is a good indicator of relative fish size, different species of fish have different sonar characteristics, so it is not always possible to distinguish fish size between varying species. The signal intensity is "normalized" for depth so that a small fish close to the boat does not appear as a large fish symbol.
ID+ adds an additional piece of information to help the user locate fish. On selected fish symbols, the digital depth of the designated fish is drawn to help locate the fish vertically. This is especially helpful in setting bait depths or for downrigger operation.
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