I would suggest you pull your radio out first and check that the aerial plug hasn't worked it's way out before trying to change you aerial. They have a habit of working loose and falling out.

Ford aerials rarely give trouble.Remove the aerial lead from the back of the radio and get a short length of wire approx 30cms long and insert it into the small antenna hole.You should now pick up some reception,if you don't ,then the radio is faulty.hth