later. so that one is very important to get. >> but as david pointed out earlier, because of the depth of the ocean floor, it can play tricks trying to locate the black box, sound carries oddly over water and given the topography, that can be difficult to locate it. >> it can be, it is broadcasting a signal, five watts, 347 mgz signal which does transfer well. there is three models of transmitters, locating beacons, one of them has a three kilometer range, second, five to seven, the third one, nine to 15. i don't know which one it had. but if you subtract the numbers,