I posted a long explanation to rec.boats.cruising, but Lionheart is on her
third new Raymarine 2KW radome, the other two being eaten alive by the
awful condensation caused by the dome being "drained" instead of
"SEALED"...breathing in and out like an old empty fuel tank every day. The
pot metal chassis is eaten away. The magnetrons RUST. The inside of the
pot metal chasis also is eaten because it's open to the humidity where the
power and data cables plug into it. Inside the receiver box looks just
awful with the zinc powder all over the receiver board....

Anyone else looked inside their Raymarine radome and found similar water
and corrosion and galvanic action?

Replacing the radome every 12 months, even free from Raymarine, is silly!