I put a huge outdoor digital aerial up for my DAB radio, when I tested it I received no more channels and no better perceived quality than I got off the 12 inch long dangly piece of wire that came with the radio.
I have a "One For All" three way aerial, (about £15) it fits straight into my DAB stack. The aerial picks up a lot more of DAB where you are. It can fit a TV as well, but as for small DAB systems with a wire you would have to connect the wire to something, or extend the wire higher up. My range of DAB stations is still pretty dire.