There will be a "hole" in the radar
return from the main mast being directly in front of the antenna
, if the mast is metal. Think of the radar
being a light source, and your mast casting a shadow. The size of the shadow will decrease the farther away the antenna
is from the mast. I can't say from experience how much of an effect this has, but alot of the radars I've seen mounted on stern poles seem to be on the starboard side, presumably to get a clear view ahead and not shadow the starboard watch area? I have interest in this topic as well, I am also considering placement location for a radar antenna and worry about genoa/spinnaker hangups.