Archived posting to the Leica Users Group, 2001/10/04

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Subject: RE: [Leica] Re: New Aviation Rules
From: "Austin Franklin" <darkroom@ix.netcom.com>
Date: Fri, 5 Oct 2001 00:08:49 -0400

> Re cellular phones and aircraft interference, let me clear up a few
> misconceptions.
>
> GSM phones perform regular location updates and send measurement reports
> back to the system using a crazy burst of signals at about 217Hz
> (modulated
> at the carrier freq). Any electrical apparatus with non-linear components
> (e.g. a diode) will demodulate this, and here's your interferer.

ANY?  Even if it's well shielded?

Do we even have GSM here in the US?  I'm not sure, I only have experience
with T/CDMA phones and systems.

> And regarding the phones chewing up capacity when in the plane at
> altitude
> ... it just doesnt work like that. A phone in a high rise can be
> 'heard' by
> dozens of base stations, but it will only ever use a carrier from one of
> them when it makes a call. The system chooses the most appropriate base
> station, based on signal strength, quality and other parameters. Handing
> over between cells is not an issue either.

> Also, the radiation pattern from base stations is aimed towards
> the ground,
> not up in the air.

That was my understanding also...

> I hope this confuses things.

You never know.

Thanks!

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