If you look closely at the rod there's a separate wire sticking out the side about 10 cms. It probably measures impedance over that 10 cm space. You can definit

If you look closely at the rod there's a separate wire sticking out the side about 10 cms. It probably measures impedance over that 10 cm space. You can definitely see him use it to measure impedance between the line and the clamp, but the first one is hard to see because it's behind the clamp. The second is far easier.