Can Alec Baldwin Crash a Plane With a Cell Phone?


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Profile Bill Walker
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Message 1192971 - Posted: 9 Feb 2012, 20:13:58 UTC - in response to Message 1192962.

However, GPS devices don't transmit. They only receive (very weak) signals from the GPS satellites and do not cause any radiation at all.


Any conductor carrying a time varying voltage is a transmitter. Digital systems can react to extremely low strength radiated fields, if the frequency matches an internal frequency (or its harmonics). For more information, sign up for my EMI/EMC lectures at ITPS Canada.
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Message 1192986 - Posted: 9 Feb 2012, 21:11:36 UTC - in response to Message 1192962.

However, GPS devices don't transmit.


Not by design. But some transmission by radio receivers is unavoidable. A radio receiver is a tuned oscillator with an output. A radio transmitter is a tuned oscillator with an input. A radio transceiver is a tuned oscillator with an input and an output.

When you put a radio receiver in a box with electronics, any oscillating signals in the receiver band will start oscillations in the receiver circuitry. Now you've got a transmitter. The folks who made the receiver don't really care, so long as those oscillations are "out of band" and don't mess with reception.

A GPS installed in an aircraft cockpit goes through lots of testing and certification to make sure it won't interfere with the aircraft systems. So did the coffee pot in the galley. So did the DVD player in the in-flight entertainment system. If it breaks, they can't just go to BestBuy to get a new one. A handheld GPS might have gone through testing to make sure that it won't explode if you short the battery. But probably not.
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Profile Gary CharpentierProject donor
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Message 1193017 - Posted: 9 Feb 2012, 22:42:44 UTC - in response to Message 1192986.

However, GPS devices don't transmit.


Not by design. But some transmission by radio receivers is unavoidable. A radio receiver is a tuned oscillator with an output. A radio transmitter is a tuned oscillator with an input. A radio transceiver is a tuned oscillator with an input and an output.

When you put a radio receiver in a box with electronics, any oscillating signals in the receiver band will start oscillations in the receiver circuitry. Now you've got a transmitter. The folks who made the receiver don't really care, so long as those oscillations are "out of band" and don't mess with reception.

A GPS installed in an aircraft cockpit goes through lots of testing and certification to make sure it won't interfere with the aircraft systems. So did the coffee pot in the galley. So did the DVD player in the in-flight entertainment system. If it breaks, they can't just go to BestBuy to get a new one. A handheld GPS might have gone through testing to make sure that it won't explode if you short the battery. But probably not.

If you have two radios listening to the same frequency, you have two local oscillators at nearly the same frequency. They will interfere with each other and sometimes add and sometimes subtract. That can play havoc with trying to read the short pulse transmissions from the satellite. Timing of the phase difference is the key and that is random and likely 99% of the time it won't be an issue. The location of the other GPS device in the plane is also an issue and likely 99% of the places it could be won't be an issue. But do you want to chance it? Never mind the coax getting damaged in the last inspection of the plane and the shield now has a hole ...

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Message 1193027 - Posted: 9 Feb 2012, 23:07:23 UTC - in response to Message 1192849.



Yes, it might be decades before random cell phone usage is confirmed as the cause of a fatal accident. Does that make it OK to kill that next plane load of people, when it can very easily be prevented?

Good for any of you if you are willing to be a guinea pig in the search for answers. Just be sure to check with everybody else on the aircraft first. They may not share your spirit of adventure.


As I've said, I hope they keep the ban.

My "spirit of adventure" has to extend to valves that when pushed too hard completely reverse direction causing rudders to point the wrong direction (737 problem, I think) or the automatic pilot that runs planes into the sides of mountains (maybe also a 737 problem?).

I'm not going to fear an MP3 player that wasn't turned-off. I don't think that lack of fear makes me especially courageous or foolish.

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Message 1194950 - Posted: 13 Feb 2012, 21:17:52 UTC - in response to Message 1192581.
Last modified: 13 Feb 2012, 21:26:37 UTC

1) I agree the risk is non-zero. However, frankly, that isn't a meaningful statistical statement. Nothing is non-zero. Moreover, we take many many non-zero risks every single day, risking not only ourselves, but our families, friends, and bystanders around us.

All you need to do is get in a car, and you are putting many people at non-zero risk. We do it anyway because the quality of life benefits outweigh the risks.

The Universe -- some information to help you live in it.

...

4 POPULATION: None.
It is known that there are an infinite number of worlds, simply because there is an infinite amount of space for them to be in. However, not every one of them is inhabited. Therefore, there must be a finite number of inhabited worlds. Any finite number divided by infinity is as near to nothing as makes no odds, so the average population of all the planets in the Universe can be said to be zero. From this it follows that the population of the whole Universe is also zero, and that any people you may meet from time to time are merely the products of a deranged imagination.

(Now I just hope the estate of Douglas Adams doesn't sue me for infringement of the incomprehensibly tortuous Galactic Copyright laws.)
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David
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Waiting for a message from a small furry creature from Alpha Centauri.


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Message boards : SETI@home Staff Blog : Can Alec Baldwin Crash a Plane With a Cell Phone?

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