hi neil, is it an aftermarket head unit, if so you might need to get a aerial booster power supply if your bee-sting is an amplified type. something like one of these, click me
The original 16v/vr6 beesting was amplified from the head unit and many after market aerial's don't have this (mine dosen't but check for an electrical box within a couple of foot of the aerial base) this is the blue wire from your head unit to the power box for the aerial and connect a direct live to this. you must also earth the aerial box. as i have all ready stated mine dosen't have the booster fitted and I have no problem with radio reception with my pioneer cd...If you do find the reception is crap, I agree with garfayliu and you should get an aerial booster.try halfrauds or the net should be about 5 or 10 quid topp's