there s been storms in this part of the ocean, which will change the salinity and the surface temperature. you might get a difference in temperature between a lower layer and an upper layer and a difference in salinity, in density. and this would affect the path of sound waves. and so the two ping signals could very well be coming from a signal source. and with all the errors adding up, they seem to be very far apart. but if you re going to look some place, this is sure a very good start. yeah. jeff, we are learning tonight that the pings detected by the ocean shield, as bill nye was just referencing, were actually at 33.3, where he said you may get a different temperature, right? a lower standard than the standard beacon frequency of 37.5 kilohertz. that s according to the pinger manufacturer. do you think this could still be the black boxes in your estimation, even at these different temperatures or different rates? there s a lot of problems with this pinger data.
in perth, 3:00 in the morning there. will, the ping detected by the ocean shield was not the same frequency we would expect to hear from a black box. what are crews there saying about that? reporter: yeah, remember when we first got the word that those chinese ships that potentially heard a ping, and we heard the 37.5 kilo hertz, and then we re hearing that these pings were like 33, and 33.2. and so you re wondering, what gives, why is it not the same number? well, the manufacturer of the black boxes says that that it still makes this a credible lead. there s still a very good chance those frequencies would have come from an in-flight data recorder or cook about it voice recorder. two factors. battery life is one. if the battery is old or the frequency can change. also the depth at which the signal is being emitted, then the water pressure surrounding the device, that can also change the frequency that s detected on the surface. so they still feel very much that these two pings tha
explanation. don t we all. it s supposed to be 37.5. but, you know, frankly, it s all we have. so if the experts and the pinger manufacturers say that over time, and both the battery degradation and the water, the effects of the saltwater can cause it to be slightly off of the property frequency, you know, that s what they re going on, and that s what we have to go with. ordinarily it is 37.5. but if the manufacturer says it s still good to go at 33.5, then sounds like a good lead. because it s the only lead we have. it is the only lead we have. let me again, because we have obtained the actual pings from i shouldn t say pipngs, the clicks, whatever it was detected over the weekend, we have it. let s roll it again.
used by bringing in more evidence on the radar tracking of this aeroplane. and the location is exactly on this track that the ships were told to go and have a look at. so there s some supporting evidence that, yes, they are the black boxes. we listened to this press conference live from angus houston, paul. you were optimistic about this, but now cnn is hearing that the frequency detected was 33.3 kilohertz, not 37.5. do you still believe that these are, in fact, the pingers, and is it an exact match? is 33 that close to 37? okay, we re talking about 10%. and we had a discussion this evening before air about the effects of temperature gradients on the transmission of different signals through water and the effects that can have with respect to frequency of signals.
sound like this with this frequency. 37.5 kilohertz was selected because it is unique from the background noise in the ocean. randy joins us now. you ve been working with these beacons all day. how much water does it need be in before it starts pinging? reporter: they can survive in depths of 20,000 feet. what we want to show you tonight is how sensitive they are. we have this tin cup here. it has a moist paper towel in it. no water in it. this is one of the pingers. we have the tester right here. i ll be quiet for a moment as we put this in and just with a moisture paper towel listen to it activate right away. [ pinging sounds ] you hear that right away. it starts to work. we also want to tell you tonight we talked to the people here who make these and said we talked a lot about the 30 day deadline for the battery to run out