Problem with a strange beeping noise coming from the wall..?!?

We have an old TV aerial on the roof of our house that we've never used (we have a satellite dish). Recently we've been hearing a strange beeping noise (first off it beeped once a minute, now it's almost constantly!) coming from what sounds like the other side of the wall of our attic. Is it possible the noise could have anything to do with an old TV aerial? Also a neighbour suggested that it could have something to do with the digital switchover..? Any thoughts would be appreciated!!