Todd,
Are you trying to tell us there are radars that operate on more than one band? I've always thought marine stuff was either X-band (9 Ghz) stuff for us small guys, or the S-band (3 Ghz) stuff for the big boys with the room for a 12' open array and $30K to spend. My understanding has always been that the X-band goes to pot in lousy weather. (Just listen to the ferrys on Ch16 in a snow storm!) The big boys use the S-band so they don't have do dial down the wave scatter stuff when it gets nasty.