Onwa Marine Electronics KR-12X8 - Manual (Page 68)

7. ARPA
WARNING
This auto plotter is not designed to replace the human eye nor make decisions for the navig-
ator. It is intended for use as an aid to navigation. Always maintain a watch while underway.
Data obtained from this auto plotter should always be double checked against other sources
to verify the reliability of the data.
This auto Plotter automatically tracks a acquired radar target and calculates its course and speed.
Indicating it by a vector, Since the data generated by this unit are based on what radar targets are
selected, the radar must always be optimally tuned for use with it to ensure that required targets
will not be lost or unwanted targets such as sea returns and noise will not be acquired and tracked.
A target echo does not always mean a landmass, reef, ships or other surface objects but can imply
returns from sea surface or precipitation. As the level of these returns varies with environment, the
operator is required to properly adjust the STC (ant-clutter sea), FTC (anti-clutter rain) and GAIN
controls to ensure that target echoes within the affected area are not eliminated from the radar screen.
The optimum settings of these controls may slightly differ between the normal radar operation and
plotting, and it is recommended to readjust them in accordance with the operating mode selected.
NOTICE
The installation must be done by a ONWA representative or suitably qualified radar technician.
Authorities require this.
Keep magnets and magnetic fields away from the equipment.
Magnetic fields will distort the picture and can cause equipment malfunction. Be sure the unit is well
away from equipment which gives off magnetic fields (speaker, power transformer, etc.).
The following items affect calculation accurary.
echo intensity
radar transmission pulsewidth
radar bearing error
gyrocompass error
own vessel or other vessel course change
Data for CPA, TCPA, ect. Are approximations only. Always use data obtained prudently.
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