Jerry Van Baren
gerald.vanbaren at smiths-aerospace.com
Tue Sep 4 20:00:36 CEST 2007
IIRC, the radio receiver ban dates back to when relatively inexpensive
aircraft band receivers (things passengers took on board, not the radios
the airplane was fitted with) were often regenerative/superregen and
thus interfered with aircraft communications if mis-adjusted (and were
often mis-adjusted by John Q. Public). After a few incidents where
passengers took radios on board to listen in to the aircraft
communications and inadvertently *prevented* aircraft communications,
all radio receivers were banned.
There is tremendous inertia in relaxing restrictions once in place,
especially where safety was once involved.
Claes Mogren wrote:
> I call bullshit on this signal restriction. How come they've
> successfully had wifi on planes without any problems? And I know that
> people have their phones on all the time while flying and I've never
> heard that it has caused a crash or even been noticed in any way. Can't
> imagine that there's any GSM signal to pick up a 30000ft anyway when you
> move at 800km/h.
> Also, if GPS is bad for the planes, how come the US is going to use it
> to navigate the planes?
> Anyway, back to OpenMoko. I agree that it's good to have the option to
> turn all wireless communication off on boot, with a timeout of 10
> seconds or so. Default should be the same settings as you had when you
> turned off though.
> Claes Mogren
> On 9/4/07, *Richi Plana* <myopenmoko at richip.dhs.org
> <mailto:myopenmoko at richip.dhs.org>> wrote:
> On Tue, 2007-09-04 at 10:27 -0700, John Seghers wrote:
> > Part of the process of receiving signals involves
> > mixing a received signal with lower intermediate frequencies (IFs) to
> > amplify the desired actual signal, while making the carrier
> signal something
> > easier to work with. See http://en.wikipedia.org/wiki/Heterodyne
> for a very
> > basic description.
> Fascinating. So "passive receivers" really aren't? Or are there classes
> of receivers which are (no amplification or very sensitive pickups)?
> Prolly off-topic, but I sure am curious. Are there no radar detectors
> which don't give off their presence?
> Richi Plana
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