so call... to talk with an insurance expert about everything that comes standard with our base auto policy. and if you switch, you could save up to $423. liberty mutual insurance -- responsibility. what's your policy? >> two ships in two spots heard potential pings 370 miles apart. are they hearing the same pinger or is one of the ships picking up something else perhaps? the signals that china's ship heard were picked up using an unconventional method. there are also good reasons to believe it. number one the frequency doesn't occur in nature. the frequency is 37.5 kilohertz and black box beacons are designed to be at that