USING THE 250DX
MENU FUNCTIONS
Speed Offset. The Speed Offset option allows the user to compensate for differences in hull design, and its effect on the accuracy of the speed measurement. If there is a discrepancy between the indicated speed
and another speed measurement device on the boat, the speed measurement can be varied to improve accuracy. Remember, the speed paddle wheel
measures speed through the water, not speed over ground.
Speed offset is remembered after power is disconnected.
Depth Offset. The Depth Offset allows the user to select the point on the boat from which the depth measurement is made. Selecting a positive value adds distance to the measurement. If the transducer is mounted 3 feet beneath the waterline, a positive 3 will show the correct depth from the surface of the water.
Another frequent use of depth offset is to show the depth beneath the deepest point of the hull. A negative value equal to the distance from the transducer location and the deepest point of the hull will have the same effect as mounting the transducer at the deepest point.
Depth offset is remembered after power is disconnected.
Filter. Filter provides an advanced level of control over the amount of detail visible
With Filter set to OFF, the 250DX displays increased 
detail, showing more thermoclines, structure, fish and even your bait when it falls within the sonar cone. However, this extreme sensitivity requires you to optimize the installation of your unit and transducer so that “noise” generated by a moving boat is not picked up by the fishfinder.
With Filter set to ON, excessive clutter often caused by interference from other fishfinders, your boat‘s engine, or from noise generated by the hull at high speeds is reduced in the display. This provides a cleaner image on the display in most cases.
With the Filter menu on screen, use the arrow keys to select the setting for your boat. When finished, press MENU to display the sonar screen.
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