themselves may be shielded, the GPS receiving antennas obviously can't
be. Otherwise they wouldn't be able to pick up the faint GPS satellite
signals.
And it is at the antenna that the signal interference would take place. The
first through fourth harmonics of the cellphone signal (depending on which
of the four RF bands the phone is operating on) sits right on top of the GPS
band and make it very difficult for the avionics to pick up the weaker GPS
signal. Sort of like trying to have a conversation with somebody in a tiled
health club shower room while someone else is loudly singing in between.
FWIW, I design RF networks for a living so I feel comfortably qualified to
speak on this subject.
-Christopher Erickson
Network Design Engineer
5432 E. Northern Lights Blvd., Suite 529
Anchorage, AK 99508
N61° 11.710' W149° 46.723'
www.data-plumber.com
On 6/1/06, Bill Sheehan <[EMAIL PROTECTED]> wrote:
>
> You're missing the point.
>
> IN THEORY, IEEE is correct. Mobile phones and other consumer
> electronics produce radio emissions, some of which are THEORETICALLY
> capable of interfering with navigation.
>
> IN PRACTICE, airline systems are shielded. You may not take a
> cigarette lighter on board with you, because the pressure difference
> may cause unexpected results; a defective lighter may explode (and
> you can't smoke on board in any case). They let you take mobile
> phones on board, but restrict their use. If there were any real
> danger of a mobile phone causing problems, you can bet your plastique-
> soled booties that you wouldn't be able to take it on board.
>
> -- Bill
>
>
>
> On Jun 1, 2006, at 4:00 PM, Christopher Erickson wrote:
>
> > First, the Mythbusters episode had nothing to do with the IEEE story
> > and the research it reports.
> >
> > Second, the interference is caused by obscuring the reception of the
> > faint GPS signals, not by directly disrupting the avionics.
> >
> > -Christopher Erickson
> > Network Design Engineer
> > 5432 E. Northern Lights Blvd., Suite 529
> > Anchorage, AK 99508
> > N61° 11.710' W149° 46.723'
> > www.data-plumber.com
> >
> >
> > On 6/1/06, Bill Sheehan <[EMAIL PROTECTED]> wrote:
> >>
> >> That's the theory, which was borne out by MythBusters. In reality,
> >> airline systems are shielded.
> >>
> >> If there really were a threat to airline safety from some twitnit
> >> deciding to call home, they'd confiscate the bloody phones. Just
> >> look at the paranoid precautions airline passengers must silently
> >> suffer nowadays.
> >>
> >> -- Bill
> >>
>
[Non-text portions of this message have been removed]
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