David VanHorn microbrix.com> writes: > I don't know that it needs to be all that powerful, it's not actually > running anything in there. > It's just that the reflected energy needs to be detectable. Doppler speed > guns aren't too powerful, and they work. Doppler speed guns are pointed at essentially point blank range at a target that is many lambdas square. The small resonator if used as a microwave microphone is at most one lambda square, assuming someone can actually put a beam on it (remember it would be in a wallet between other coins). The radar cross section for a microwave speed gun is huge and its power is not so low (tens of mW afaik). A laser speed gun will have double the range for the same beam power because for the laser the radar equation is not valid (the laser is inverse square law without a retroreflector). Brooke said it could be used in a 'gate' type of reader but the article mentions 'tracking'. This implies it works stand-alone imho. It will be fun to watch how this ends. Peter P. -- http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist