Our motorhome was home in the garage when I decided to grease the front kingpins and steering joints. In order to fit under it I raised the front with the leveling jacks. As the coach went up I heard a crunch, stopped raising and wondered what had hit. Suddenly realized that when installing a new DVD on the TV I had wound up the antenna to check TV sound outputs several days before. The antenna had hit a stiffener at the crown of the garage roof. No damage but sure felt stupid, no one was there but me and I haven't told the DW.