Octavia Radio

Talking to my dad today who says he has a problem with the radio in his Octavia. Every time he passes under a bridge when listing to the radio (both FM and AM) he will lose his signal and will just he a hiss. Using my Fabia at the exact same places you don't get this! He also noted that you could hear the indicators over the radio. So before we take it to the dealer I thought I would post it hear to see if you could come up with anything. Is it possibly a fault with the suppressor?:confused: