Raymarine Pathfinder Radar Scanners - Manual (Page 19)

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• Radar operates at the line-of-sight, so a high mounting position gives bet-
ter long range performance.
• Surrounding large objects, in the same horizontal plane, can interfere
with the radar signal and cause blind areas or shadow sectors and false
targets on the radar screen (see below).
However, do not mount the scanner so high that it is affected by the pitching
and rolling of the vessel. In addition, you may need to lower the scanner to
avoid creating a shadow sector underneath the scanner’s beam.