A power conditioning unit with maximum power point tracking for a dc power source in a photovoltaic panel is provided. An adaptation ring is provided on the holder; the adaptation ring containing multiple gaps. The feeding point and a point on the ground plane define an inputoutput port for said passive antenna set. Adjacent the protrusion and between the rollers of each pair is a prong that selectively biases one or the other of the rollers of the pair away from the protrusion.