top | item 12000460 (no title) wmt | 9 years ago Why not radios? I don't see any obvious benefits in using sound waves over the RF spectrum. discuss order hn newest sevensor|9 years ago The useful parts of the EM spectrum are crowded and regulated. Sound is anybody's game.
sevensor|9 years ago The useful parts of the EM spectrum are crowded and regulated. Sound is anybody's game.
sevensor|9 years ago