Neil Hopcroft

A digital misfit

“I’m on a plane”

“It is sometimes possible to make cellphone calls while aboard a plane, but only when travelling at low altitude, in range of cellular network masts….concerns that they might interfere with aircraft electronics….However, American Airlines says extensive testing has so far revealed no interference.”


Categories: Memories.

/ 7 Comments

7 comments

  1. neilh

    Perhaps more problematically, when you’re on a plane you are travelling faster than the network can hand you over from one base station to the next….

    Reply
  2. neilh

    The problem is in the phone, not the basestation, it won’t retrain onto a new station for some period of time after its last move, this is supposed to prevent problems of continuous retraining when in, say, a built up area with many reflections from buildings.

    Reply
    • marvelousmrchip

      I seem to remember several of the September 11 victims making cellphone calls from the various planes to assorted members of their family to say goodbye. Or was it all a conspiracy?

      Also, you can make mobile calls from planes that offer their own facility/phones (at a price). Not sure they`re using GSM, though!

      Also, the main reason people aren`t allowed to use mobiles on planes (apart from taxiing after landing now, it seems) is the unknown effect it has on fly by wire aircraft. I remember several instances of Boeings and Airbuses having unexplained steerage problems (e.g. left instead of right – seriously). It was around the software testing strategies area. The s/w people could not simulate this any which way. That, I believe, is the main reason they banned mobiles. Am I wrong? (It does happen!)

      Reply
      • neilh

        9-11 phone calls were special cases, they were going to die anyway so it didn’t really matter if their call brought the plane down, also I guess they were mostly on the old analogue system the states still uses.

        Planes are shielded well enough to deal with the kind of radiation phones will give off – think what happens if a plane is struck by lightning, and theres a good deal more power in that than you’re likely to get from a 3110.

        The left/right problems are mostly explainable, just that when the crash is reported the same day they don’t yet know what the explanation is. Most of the time its a compensation for a wayward instrument which isn’t handled correctly.

        There is an incredible amount of shielding and error compensation that going into these things, theres nothing that a measly 4Watt transmitter can interfere with.

        Reply
  3. neilh

    GSM (and some other protocols) already have the concept of a pico cell, there aren’t yet any in the UK as far as I’m aware, though. These are low power, akin to wifi, but running a GSM stack. So that would be one possibility. Maybe a better solution would be to have some kind of ‘roaming’ solution where you can take out your SIM and put it into the handset in your seat, or have some kind of docking station that links you direct to the onboard phone system, rather than using GSM within the plane itself.

    Reply
  4. neilh

    Re: Pico cells – I want one.

    …but thats OK, because by the time this is likely everyone will have a GSM/802.11bfg dual-stack phone anyway making the pico-cell redundant.

    Reply
  5. neilh

    Re: Pico cells – I want one.

    Two years, perhaps, dunno really, depends on infrastructure, but seamless roaming between wifi and wcdma is going to take a bit of testing, its difficult enough doing the handovers at the moment let alone going from one protocol to another.

    Reply

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