>> today's unconfirmed news that a chinese patrol ship may have detected a pulse signal in the search area for flight 370 raises all kinds of questions. our renee marsh joins us now from washington. we know the sound picked up by the chinese ship is the standard frequency from the pingers at least from what's being reported and this doesn't necessarily mean it's a slam dunk and there's a lot of skepticism. why? >> there is a lot of skepticism. this report has really peaked our interest simply because of that key information coming from chinese tv in that the sound was that standard frequency of the pinger 37.5 kilohertz. you have the manufacturer on our air saying this tre quency is unique to these pingers and there's not a lot in nature that