jim at netgate.com
Tue Sep 4 19:59:19 CEST 2007
On Sep 4, 2007, at 7:50 AM, Claes Mogren wrote:
> I call bullshit on this signal restriction. How come they've
> successfully had wifi on planes without any problems?
Have you tried all WiFi devices on all planes?
> 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.
Note that you're typically not moving at 800km/h relative to all
towers. In fact, if you can see a tower (LOS), then its likely not
in front of, or behind the plane, so the
relative velocity could be quite low.
> Also, if GPS is bad for the planes, how come the US is going to use
> it to navigate the planes?
> gps_satnav_air_traffic_for_america/ )
What if your GPS interferes with their GPS, because it happens to
have a broken ground on the shield on its oscillator?
(see previous message).
> 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> wrote:
> On Tue, 2007-09-04 at 10:27 -0700, John Seghers wrote:
> > Part of the process of receiving signals involves heterodyning--
> > 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
> 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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