A fuel cell stack generates power using hydrogen-rich gas obtained by reforming vaporized methanol in a reformer. In order to reduce a superposition of signals that have traveled along different directions along the closed circuit, the at least one slide track is configured to have electric losses resulting in an amplitude of an electrical signal coupled into the slide track being reduced by at least 6 dB, preferably 10 dB, during a passage of the signal along one entire length of the slide track. A shorter puller wire has a distal end anchored at or near a distal end of the proximal deflectable portion.