Not an easy way around the scratches you get with the magnetic antennae. That darn magnet draws moisture which in turn draws debris underneath it. On the run, I clean mine every morning to get dry the moisture from underneath it. I have used a small piece of clear 4 mil polyurethane but still have to clean it everyday and I don't know if it helps 'cause the magnet slips on the plastic. Keeping the area clean with a good coat of wax is about as effective as any.
"Ready to Roll Roy?"
78 WS6 TA, Original Owner, Martinique Blue, Coupe
79 WS6 TA, Mayan Red, T-Tops
and a couple of others that will remain nameless!