i read about a month ago that cell phone charging is about to be 'revolutionized.' Apparently, cell phones of the near future will have a wireless charging system where you plug a radio transmitter into the wall, and the cell phone recieves the signal and uses it to charge it's batteries. My question is, why can't you just take pre-existing radio freq/cell freq/etc freq signals out of the air and use them? Sure they're not very powerful signals but how many times have you been in a store when someone next to you makes a phone call. there's got to be some power there! no?