Dab signa

I have a Yamaha YSP-30D sound bar which has Dab radio inbuilt. The aerial that was suplied doesn't give very much of a signal at all. The sound bar is sat under the telly and on the shelf above the Sky+ HD box. What I'm wondering is, can he aerial be used if I use a splitter from the telly or Sky box? Or is it a seperate signal required? If it's a seperate signal what's the best indoor digital aerial for this application. Bearing in mind it needs to go behind the telly stand so it doesn't stick out like a sore thumb.

Thanks alot.