It depends on the station, and the tuner.
Where i am, i can reliably pick up 2 strong stations with no antenna attached on all but one tuner i've tried. But thats a horrible way to test a tuner.
Simple dipole - take a length of speaker wire (6-8') and separate 28 1/2" of the two wires on one end. hook the other end to your antenna inputs. mount it up like a T and voila. Nice 300ohm cable works better, but standard 18ga speaker wire works just fine, and will give you a much better idea of what that tuner can do.