> "power gathered from ambient radio signals transmitted by a base station up to 31 feet away" Seems pretty useless. Better would be to use capacitor and crank

> "power gathered from ambient radio signals transmitted by a base station up to 31 feet away" Seems pretty useless. Better would be to use capacitor and crank handle. And first GSM phones were also battery free. It was van stuffed with equipment powered by a generator ;-)