I don't get it, one of the nice things about mounting the radar
sufficiently aft of the mast
on an arch is that one doesn't get much shadowing of the radar image. I've done this with two of my boats and don't have a problem "seeing" right through the mast. Now I don't mean that I get 32 miles on my 32 mile radar like you would 30 feet up.
Like the famous physics slit experiment
with light waves, radar waves form interference
patterns around the mast and, in essence, "reconstruct" most of the energy of the original (and reflected) wave front to "see" right through the mast. When the radar is smack tight up against the mast you lose the rearward "sight" due the effectively huge mast crossection so close to the transponder.
So, I wonder what's up with yours?