Natural Radio recordist Steve McGreevy was in Canada last year for the Northern Lights: not to see them, but to hear them. You can do that, if you have the right equipment. And Steve's got a van full. Producer Barrett Golding introduces us to Natural Radio -- the sound of earth's magnetic field. Like the auroral lights, Natural Radio effects tend to be stronger around the spring and fall equinox, and near the earth's poles. So whenever Steve gets a chance, he heads north, into the wilderness, away from electrical interference, where the listening is best. There's a double CD of Steve's Natural Radio recordings called "Electric Enigma," put out by Dutch East India Trading.