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  1. #21  
    The "do not remove this tag" bit is for stores selling the matresses. Not for consumers. Its so you can tell all the pertinent information when you're attempting to purchase the thing.

    Government warnings generally are a good thing. Without government warnings and oversight you would be eating rat droppings in your canned food.
  2. #22  
    another major reason they don't allow cell phone usage in the air is because it can and sometimes does knock out service for lots of people at once. at that altitude a cell phone can try connecting to dozens of towers at once.
  3. leonidm's Avatar
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    #23  
    cell phones do not interfere with planes equipment, otherwise they would be banned from carrying on the plane. It's like saying you can bring grenade or rocket launcher to the plane but don't use it during the flight it might interfere with integrity of the plane .
    The reasons they don't want you to use it on the plane:
    1)Handoffs are calculated and optimized for the ground communication . if flying over the rural area with the small cells at a high speed - you'll be going through the infinite loop of handoffs, changing cells too fast: neither base stations nor cell phones are designed to do this reliably at high speed. This may confuse the equipment and most importantly will cause dropped calls for the caller himself and possibly others on the ground using the same pair of frequencies. Dropped calls is the main parameter for performance measurement of the local operators - so this is why AT&T wouldn't wont you to use their network while on the plane - this will break their stats
    2) They want to make money from GTA phones
    3) It's a public place and they don't want people to complain about sitting next to someone who was talking on the phone during entire flight, screaming at his wife
  4. #24  
    FAA regs state that portable electronic devices can be used at the pilot's discression..... but from what I understand it is really the FCC that gets upset about the airborne calls. Either way... it is still the Feds that would be concerned about it..

    (I have never heard about an accident caused by a cell phone transmission though---- There are tons of radios in the cockpit of most planes)
  5. #25  
    "3) It's a public place and they don't want people to complain about sitting next to someone who was talking on the phone during entire flight, screaming at his wife"

    I was with you until this point, talking during the entire flight doesn't take a cell phone or even an interested party. Chatty passengers are just inevitable. Cope.
  6. #26  
    I hope you are trying to be funny, because nobody is buying that.

    Originally posted by dcopperfield
    By the way, I do work for a government agency and it was a commercial flight... So it was an "official" test... Not an ill-informed civilian
  7. #27  
    Everyone in this thread is talking about tower hopping as if they are on a GSM network.

    As far as Treo 600's on Sprint are concerned, CDMA is not likely to have any problem with passeners passing thru their cell sites at 600mph.

    Consider that CDMA phones do not "tower hop" the same way that GSM phones do. a CDMA phone is always broadcasting on the same channel, with it's same id code. It never changes through the entire call, this alleviates problems, and presents interesting challenges as well. The towers simply become aware of a user moving into it's range when the users power signal becomes signigicantly high enough to be noticed by the tower. In fact in some cases, it is possible for up to 3 towers to be actively working together to receive one users signal and decide who is doing a better job of it.

    If to many users move into a cell site, the cell coverage for that tower shrinks and users on the edge of the area drop. This is to say that the tower can not just dissallow users already on a call from moving in to it's area because all CDMA phones are using the same wideband channel. That being said when to many users move into a towers coverage area, the tower is forced to take them in. This is why CDMA has some issues if not deployed densly. Perhaps the tower can dissallow new calls but CDMA is highly dependend on dense tower placement to avoid it's shortcomings.

    So this so called hand off screwing up GSM systems (at 600MPH) might be true, but this kind of irratation for the towers is something CDMA deals with by design. I doubt just beause a CDMA user is moving more rapidly does much of anything to other users on the network that they don't already have to suffer from more than any other user coming or going between cell sites.

    As for interference. Those stupid reports you read about aireplan interfernce never make the distinction between CDMA and GSM. Since CDMA broadcasts on such a wide band, it's power level at any given smaller frequency range is pratically undetectable. Why a CDMA phone, or device for that matter would cause any interference on a plane is beyond me. A gsm phone however broadcasts on a much narrower band such that the power level in the band is much much higher, with a greater change of interferiing with something.

    The military was using CDMA for years (still is?) because it's very difficult to detect and pickup because of the wide band nature of CDMA. CDMA transmission appear as nothing more than atmospheric static on any non CDMA receiving equipment. How that could interfere with electronics in general is beyond me.

    I'de welcome some comments on my assumptions.
  8. #28  
    Originally posted by superjimbo801
    Everyone in this thread is talking about tower hopping as if they are on a GSM network.

    As far as Treo 600's on Sprint are concerned, CDMA is not likely to have any problem with passeners passing thru their cell sites at 600mph.

    Consider that CDMA phones do not "tower hop" the same way that GSM phones do. a CDMA phone is always broadcasting on the same channel, with it's same id code. It never changes through the entire call, this alleviates problems, and presents interesting challenges as well. The towers simply become aware of a user moving into it's range when the users power signal becomes signigicantly high enough to be noticed by the tower. In fact in some cases, it is possible for up to 3 towers to be actively working together to receive one users signal and decide who is doing a better job of it.

    If to many users move into a cell site, the cell coverage for that tower shrinks and users on the edge of the area drop. This is to say that the tower can not just dissallow users already on a call from moving in to it's area because all CDMA phones are using the same wideband channel. That being said when to many users move into a towers coverage area, the tower is forced to take them in. This is why CDMA has some issues if not deployed densly. Perhaps the tower can dissallow new calls but CDMA is highly dependend on dense tower placement to avoid it's shortcomings.

    So this so called hand off screwing up GSM systems (at 600MPH) might be true, but this kind of irratation for the towers is something CDMA deals with by design. I doubt just beause a CDMA user is moving more rapidly does much of anything to other users on the network that they don't already have to suffer from more than any other user coming or going between cell sites.

    As for interference. Those stupid reports you read about aireplan interfernce never make the distinction between CDMA and GSM. Since CDMA broadcasts on such a wide band, it's power level at any given smaller frequency range is pratically undetectable. Why a CDMA phone, or device for that matter would cause any interference on a plane is beyond me. A gsm phone however broadcasts on a much narrower band such that the power level in the band is much much higher, with a greater change of interferiing with something.

    The military was using CDMA for years (still is?) because it's very difficult to detect and pickup because of the wide band nature of CDMA. CDMA transmission appear as nothing more than atmospheric static on any non CDMA receiving equipment. How that could interfere with electronics in general is beyond me.

    I'de welcome some comments on my assumptions.
    You are correct about Sprint. In fact this article specifically mentions that Sprint's signal would not cause a problem.
    << My command as we escape Palm HQ with a new Pre 3>>.

    Treo 300 >> Treo 600 >> Treo 650 >> Treo 755 >> Instinct >> Pre- >> TouchPad
  9. #29  
    In today's high emphasis on security, I can affirmatively say that cell phones cause ZERO threats. If they seriously were risks involved, they would not let you travel with them, they would be confiscated at security.

    Just think, terrorists could bring a flight down not by the force of hijacking, but my simply turning on their cell phones ???? C'mon !
  10. LGA
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    #30  
    My sister-in-law worked for the Cellular Telephone Industry Assoc. She always said that the reason for not using phones on planes was a billing issue and companies not knowing who to charge?

    I've always followed the rules but am curious. Do the calls made in airplanes show up on your bill?
  11. #31  
    I can't imagine why they wouldn't show up. If your phone is connected to your providers tower, or a roaming partners tower, why wouldn't it show up.
  12. #32  
    They won't let you on the plane with fingernail clippers, but they'll let you take your cell phone on? Puhlease -- the Honor System for Inflight Safety?

    If it was dangerous, you wouldn't be allowed to bring it on.

    Period.
    John
  13. #33  
    They won't let you on the plane with fingernail clippers, but they'll let you take your cell phone on? Puhlease -- the Honor System for Inflight Safety?

    If it was dangerous, you wouldn't be allowed to bring it on.

    Period.
    John
  14. #34  
    Originally posted by jbeans
    They won't let you on the plane with fingernail clippers, but they'll let you take your cell phone on? Puhlease -- the Honor System for Inflight Safety?

    If it was dangerous, you wouldn't be allowed to bring it on.

    Period.
    There is some pretty scary reasoning going on in this forum...
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    #35  
    Most teenagers just fly with the phone turned on in their pants. I'd guess in a flight with 100 cell phones are least 10 are on by mistake.

    The bluetooth scene is also active.

    I turn off my phone, but many people don't even know.

    If the airlines cared they'd have an emission sensor to detect unwanted signals.
  16. #36  
    like I said...

    Anyway, you can make an argument that the airlines shouldn't care, or that they don't care very much, but it's obvious that they do care... hence they ask you to turn the phone off.
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