Furuno FEA-2807 - Rain Clutter; How to Control Video Processing; Echo Overload Condition

23. Radar Overlay
23-5
23.4.4 Rain clutter
The rain clutter control removes rain clutter from the radar echo image. If you get radar overlay video through LAN
from FAR-2x07 radar, use the rain clutter control on the radar. When you adjust the rain clutter, "Noise" is
automatically switched ON in order to display low-level radar images.
23.4.5 How to control video processing
Interference rejector: The interference rejector suppresses mutual radar interference that may occur in the vicinity
of another shipborne radar operating in the same frequency band. Three options are available: OFF, IR1 and IR2.
Select suitable level to reduce interference from other radars. Select OFF when no noise exists, so as not to miss
weak targets.
Echo average: You can turn echo averaging on or off. Scan-to-scan correlation averages echoes over successive
picture frames to distinguish real target echoes from sea clutter. The choices are EAV1, EAV2, EAV3 and OFF.
EAV1: Helps distinguish targets from sea clutter and suppress brilliance of unstable echoes.
EAV2: Distinguishes small stationary targets such as navigation buoys.
EAV3: Stably displays distant target.
Echo stretch: Echo stretch emphasizes radar echo to increase detectability of targets. "ES1" emphasise both noise
and target level echoes while "ES2" emphasizes only target level echoes.
Echo stretch ES2 Echo stretch OFF
Clear: Removes noise from the screen. Select LOW or HIGH according to amount of noise. Select OFF when no
noise exists.
Noise: Radar echoes can be displayed with gradation of green color.
23.4.6 Echo overload condition
When the number of targets on the screen exceeds the capacity of the CPU, the warning "Radar Overload" appears
in yellow on the status bar. The gain is temporarily lowered automatically then gradually raised. If the overload
condition continues, the above-mentioned process is repeated. If this occurs, lower the gain (from the keyboard or
the GAIN dialog box) to erase the Radar Overload indication.
When the overload condition occurs, do the following: