From: "Ian Buckner"
Subject: Re: old cellphone reuse/salvage and schematics/tech info?
Date: Thu, 9 Jan 2003 11:58:10 -0000
Organization: Agilent Technologies
NNTP-Posting-Date: Thu, 9 Jan 2003 11:58:12 +0000 (UTC)
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"SpamLover" wrote in message
> >> their LO's and
> > > transmitter spectral output has to be squeaky clean
> Yeah, in a pig's eye....
> Think of avionics:
> it's FORBIDDEN to use cellphones on planes, although the avionics
> should be immune from out-of band signals.
> I thought this was bullshit until I had a truly bizarre incident.
> I was at Boston Logan, flying out to Chicago, and I carried an old,
> supposedly high quality, European GSM phone, ___900 MHz ONLY___.
> On arrival, not only I discovered that my thoroughly unusable phone
> (which I had kept off for a week) had switched on accidentally in my
> bag. IT ALSO HAD RECEIVED A TEXT MESSAGE FROM ITALY. I later checked
> with my provider, who confirmed that a message was delivered while I
> was in the US.
> This means it managed a successful RF and protocol handshake,
> validation, and transaction, on a frequency is was not at all
> to cover.
> I can only guess that I was very close to a 800 MHz US GSM BTS, and
> that signals somehow broke thru out of band both ways.
> From then on, I took the airline cellphone ban much more seriously,
> and claims of spectral purity much less so!
The US has some 900MHz GSM networks, so your phone may well
have just been doing what it should.
There were some tests done on commercial aircraft for field strengths
from various sources, including the use of cellular phones. The
field strength in the cabin by a very large margin was leakage from
However, use of mobile phones is an unnecessary extra risk, and could
also cause network problems (hand-off assumptions in the network
don't include 600mph speeds, and the large coverage due to the extra
height could be a problem).