Shadow areas and false echoes

Mount the Radar scanner away from large structures or equipment, such as engine stacks, searchlights, horns, or masts. These objects may cause shadow areas and false echoes. For example, if you mount the Radar scanner on a mast, echoes from other targets may be reflected from the mast. Wet sails may also cause shadow areas, so Radar performance may be reduced in the rain. It is particularly important to avoid shadow areas near the bow. Raising or even lowering the Radar scanner may help to reduce these effects.

In shadow areas beyond the obstruction there will be a reduction of the beam intensity. There may be a blind sector if the beam intensity is not sufficient to obtain an echo from an object. This may occur even at close range. For this reason the angular width and relative bearing of any shadow area must be determined at installation.

You may be able to detect shadow areas or false echoes on your multifunction display. For example, sea clutter can be used as a good indicator of blind arcs. Dark sectors on the Radar display indicate possible shadowed areas. This information should be posted near the display unit and operators must be alert for targets in these blind areas.