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Planes & Cell phones
Recentingly, in another thread, cell phones and planes came up. I
thought others might be interested in these links. http://www.eweek.com/article2/0,1759,1568024,00.asp http://wirelesscabin.com/ http://www.wired.com/wired/archive/1...art.html?pg=12 The general theory on modern cell phones in flight, goes like this: The FCC also has a ban because when you're in flight, you're always at least 6-8 miles away from the nearest cell tower. You end up communicating with too many towers and bogging down the network. One or two such calls is tolerable, but a whole plane load moving through would disrupt the ground-based users of the network. Remember, the farther you are from a tower, the more power your cell phone uses to communicate with it's tower; up to 5-watts. Worse, a plane full of 5-watt transmitters causes terrestrial interference problems for the land cell users, in a large radius around the plane. This picocell concept (covered the above links) solves both problems by moving the nearest cell tower to just a few feet away from the phone. Therefore, the phone kicks into its lowest power tx setting, and never talks to any other tower. Of course, I don't think you can expect on in a small GA plane anytime soon. I also found a quote that went like this: "The restriction against cell phones is an FCC regulation and applies to all aircraft that can fly over a certain speed (maybe 200 kts?). Quickly switching cells during high speed flight causes all sorts of problems on the cell network." Can anyone confirm such an FCC regulation as it relates to airspeed? I must admit, from I understand of the subject, it does make sense. Just the same, confirmation would be great. Lastly, can anyone confirm first hand accounts of cell phones actually causing some type, instrumentation or radio interference? At worst, hopefully this will be some food for thought. Thanks! Cheers! |
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"Greg Copeland" wrote in message
news Recentingly, in another thread, cell phones and planes came up. I thought others might be interested in these links. http://www.eweek.com/article2/0,1759,1568024,00.asp http://wirelesscabin.com/ http://www.wired.com/wired/archive/1...art.html?pg=12 The general theory on modern cell phones in flight, goes like this: The FCC also has a ban because when you're in flight, you're always at least 6-8 miles away from the nearest cell tower. You end up communicating with too many towers and bogging down the network. One or two such calls... Here's a needed clarification. Are there still problems when the phone isn't making a call, but just sitting there listening to the network? I know such a phone is continuously acquiring the next tower down the road. Would it be true that the problem with passive phones is the same as with active ones, but to a lesser extent? -- David Brooks |
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On Tue, 20 Apr 2004 12:21:33 -0700, David Brooks wrote:
"Greg Copeland" wrote in message news Recentingly, in another thread, cell phones and planes came up. I thought others might be interested in these links. http://www.eweek.com/article2/0,1759,1568024,00.asp http://wirelesscabin.com/ http://www.wired.com/wired/archive/1...art.html?pg=12 The general theory on modern cell phones in flight, goes like this: The FCC also has a ban because when you're in flight, you're always at least 6-8 miles away from the nearest cell tower. You end up communicating with too many towers and bogging down the network. One or two such calls... Here's a needed clarification. Are there still problems when the phone isn't making a call, but just sitting there listening to the network? I know such a phone is continuously acquiring the next tower down the road. Would it be true that the problem with passive phones is the same as with active ones, but to a lesser extent? -- David Brooks Well, first let me say that I am NOT a subject matter expert on this, so please, take my comments with a grain of salt. When you speak of active versus passive, do you mean a phone being actively used for calling versus a phone simply turned on? I'll assume that's what you mean. A phone that is not actively particpating in a call is still periodically attempting to locate it's best tower. It may be sharing additional tidbits as well, I'm not sure. Nonetheless, if it's transmitting, it's causing these problems. Like you, I suspect that it is causing problems, just to a lessor extent. If you have a phone, like mine, which periodically blinks, that blink means it just transmitted. AFAIK, it's the fact that the phone is transmitting, especially at 5-watts, that is causing some of the problems, without regard for the content that is being transmitted. The fact that you're traveling at a high rate of speed, probably causes more frequent tower contacts (and tower hops) from your phone, however, that's purely speculation on my part. |
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I think you have too much time on your hands...
cheers ... denny "Greg Copeland" wrote in At worst, hopefully this will be some food for thought. Thanks! Cheers! |
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I think you have too much time on your hands...
cheers ... denny Actually, I think it's a cool topic. I'd be willing to fly slower than 200 knots if it meant I could legally use my cell phone in the air! :-) -- Jay Honeck Iowa City, IA Pathfinder N56993 www.AlexisParkInn.com "Your Aviation Destination" |
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Jay Honeck opined
I think you have too much time on your hands... cheers ... denny Actually, I think it's a cool topic. I'd be willing to fly slower than 200 knots if it meant I could legally use my cell phone in the air! :-) Cirrus 1234A: XXX Center, Cirrus 34A would like to slow to 190. XXX Center: Cirrus 34A, why? Cirrus 1234A: I need to phone home. -ash Cthulhu for President! Why vote for a lesser evil? |
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"Ash Wyllie" wrote in message ... Cirrus 1234A: I need to phone home. "SHUT UP AND FLY!!!" : My instrument instructor is also a real estate agent. Her cell phone rang during runup yesterday and she confirmed a closed sale, but not without difficulty. -c |
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gatt wrote: My instrument instructor is also a real estate agent. Her cell phone rang during runup yesterday and she confirmed a closed sale, but not without difficulty. My wife forwarded me an Andy Cap cartoon yesterday. Some dude is chatting on the phone at the pub trying to set up a business deal. He asks Andy if he has the time. Andy says "Yes, it's exactly two minutes before that phone goes through the window." Love it. George Patterson None of us is as dumb as all of us. |
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Greg Copeland" wrote in message
news snip The general theory on modern cell phones in flight, goes like this: The FCC also has a ban because when you're in flight, you're always at least 6-8 miles away from the nearest cell tower. You end up communicating with too many towers and bogging down the network. One or two such calls is tolerable, but a whole plane load moving through would disrupt the ground-based users of the network. Remember, the farther you are from a tower, the more power your cell phone uses to communicate with it's tower; up to 5-watts. Worse, a plane full of 5-watt transmitters causes terrestrial interference problems for the land cell users, in a large radius around the plane. snip Huh? Maximum output of most handheld cell phones is 0.6 watts with the old in-car and bag phones going up to 3 watts. It can't output more than it's maximum no matter how far you are away from the tower. The radius of interference from 0.6 watt phones transmitting from inside an aluminum can would be rather small. And it's a little hard to imagine a plane full of people with bag phones. I also found a quote that went like this: "The restriction against cell phones is an FCC regulation and applies to all aircraft that can fly over a certain speed (maybe 200 kts?). Quickly switching cells during high speed flight causes all sorts of problems on the cell network." The switching is done in a fraction of a second. The most that would happen is a dropped call. |
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On Tue, 20 Apr 2004 16:35:03 -0500, FUji wrote:
Greg Copeland" wrote in message news snip The general theory on modern cell phones in flight, goes like this: The FCC also has a ban because when you're in flight, you're always at least 6-8 miles away from the nearest cell tower. You end up communicating with too many towers and bogging down the network. One or two such calls is tolerable, but a whole plane load moving through would disrupt the ground-based users of the network. Remember, the farther you are from a tower, the more power your cell phone uses to communicate with it's tower; up to 5-watts. Worse, a plane full of 5-watt transmitters causes terrestrial interference problems for the land cell users, in a large radius around the plane. snip Huh? Maximum output of most handheld cell phones is 0.6 watts with the old in-car and bag phones going up to 3 watts. It can't output more than it's maximum no matter how far you are away from the tower. The radius of interference from 0.6 watt phones transmitting from inside an aluminum can would be rather small. And it's a little hard to imagine a plane full of people with bag phones. Hmm. Everything I've ever read says that maximum output is 5-watts. I'm not saying that's right, but that has been a constant. I'm not sure how far you could even transmit on 0.6 of watt. I also found a quote that went like this: "The restriction against cell phones is an FCC regulation and applies to all aircraft that can fly over a certain speed (maybe 200 kts?). Quickly switching cells during high speed flight causes all sorts of problems on the cell network." The switching is done in a fraction of a second. The most that would happen is a dropped call. People forget that cell switching is not magical. And it's certainly is not zero cost. I must admit I do not fully understand everything that goes on, but I am sure it's not as simple as you imply. Everytime a call switches cells, it creates lots of work for the cell network to make sure only a single tower handles that call. So, while it may take a fraction of a second from a given phone and a given tower, there is lots going on behind the scenes. Worse, instead of it going on with one, two or maybe three towers, now it's causing a flurry of on twenty or more (highest estimates I've read) towers. Let's also not forget that each tower can only process and multiplex n-number of signals at a given time. DSPs, just like your CPU, does have finite capacity. During cell switching, as I understand it, this finite resource is being used on each tower in contact with the phone. So, to say, "it causes all sorts of problems on the cell network", does seem like a spot on statement to me. |
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