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FEMA To Use Cell Phone Signals To Find Survivors
twistah writes: "CNN had an interview with a representative of the Federal Emergency Management Agency (FEMA), the agency helping with the New York WTC rescue effort, who said that Lucent has given them technology to trace the signal of cell phones. The idea is that people will give them phone numbers of cell phones and pagers of people missing due to the WTC collapse, which FEMA will call and attempt to trace the signal to find the missing people. FEMA has now put this information on their web site, and are dubbing it the 'Wireless Emergency Response Team.'"
Actually, it would be nearly useless in this case. GPS signals are very, very weak and can blocked by as little as a sheet of aluminum foil or a few millimeters of water. A GPS receiver under all those tons of concrete and steel would never be able to aquire and track.
Except in this case the location cached before the collision would be something like "1 World Trade Center, NE corner, floor 45 through 55". (GPS's vertical accuracy is much worse than it's horizontal accuracy.) Now add the fact that the nearest cell tower was on the roof, and it went offline immediately after the collision. Now add the fact that floors 45 through 55 are now laying in a pile with the other 100 floors. That cached position will likely be hundreds of feet from where the phone ended up - and that's assuming the person and phone ended up in the same place.
I'm not saying that GPS in cells phones is or isn't a good idea. All I'm saying is that it wouldn't be likely to have helped locate anyone in this case. The only way to find and rescue the people with those cell phones is to trianglate the signals from the phones.
They're trying to clear the subway tunnel under the building to see if anyone actually on the platform under the towers survived. The problem is that water mains have burst, flooding the tunnels and filling them with debris. At present I think they're a third of the way there.
Instead, they're only trying to get a very general location of the phones, to determine whether they're at "Ground Zero" or not. If not, they could potentially be used to find if somebody's at a hospital in a coma, or if they somehow got out of NYC in time and for some reason haven't been able to contact someone.
These phones aren't really being used to locate the survivors, they're being used to gain some clue as to whether a person is buried, or might have survived. It won't do a great job of locating people, but it will help discriminate if a person is "likely dead" or "might have gotten away."
I also heard that no actual calls have to be made to trace a phone's location, but I'd guess that it must at least be turned on and able to receive a call. And yes, as many posters have said, batteries are going to be a problem this many days later. But any more information on what happened to these people will surely be welcomed by their families.
-- Imagine how much more advanced our technology would be if we had eight fingers per hand.
If you could get a cell phone to answer a special emergency incomming call, and if you could place a cell tower close to the site - you could do a triangulation of the vicem by setting up three loude noise makers spaced far appart. Each would trigger in sequece, and a triangulation could be made by determining how long the cellphone took to hear the noise. This would allow rescue workers to fin the locations of the phone - even if the GPS signal can't get to the phone, the noise could.
Moneyed corporations, non-working 'poor' and criminal prisoners are turning productive citizens into tax-slaves.
Well, the microwave oven certainly does shield users from the microwave emissions. But it's not terribly effective outside a certain frequency range.
The actual cooking area is tuned to the microwave frequency in use - around 2.45GHz. If you operate a microwave with the door open, it won't do you a lot of good, but the radiation *away from the direct "beam" of microwaves* is incredibly weak.
Now, mobile phones (UK GSM, but others are similar) tend to work around 900MHz for low band, and 1800MHz for high band. It's not really near the resonant frequency of the cooking chamber, so doesn't get absorbed (can you say "Helmholz bottle"?)
Finally, this is also why mobile phone cell towers are *not* dangerous - a microwave oven uses a very specific frequency, at very high power, from a distance of *inches* to cook food. A cell tower uses a lower frequency, with very low power (often as little as 10w), from much further away...