Roof mount DAB antenna - should do FM/AM as well if youwant to invest a bit more time, effort and cash!
http://www.caraudiodirect.co.uk/con-ct27uv57-kit-connects2-fmdab-roof-mount-aerial.html
http://www.caraudiodirect.co.uk/con-ct27uv57-kit-connects2-fmdab-roof-mount-aerial.html