On Tue, 16 Feb 2010 18:29:10 +0000 Graham Jones <grahamjones...@googlemail.com> wrote:
> You are both right. RF absorption is a combination of amount of > material and its properties. I think the issue with trains is > limited to newer ones with special windows (I think they are > conductive - some cars have them too). The combination of > shielding from the roof and windows makes it practically > impossible to get a fix. I was surprised that I managed to get > a fix in a jet aircraft a few months ago - I would have expected > this to be a good shield too. [...] You were probably sitting in a window seat, right? Getting a fix from a window seat is usually not a problem, but I was not able to get a fix elsewhere. I have tracks from several flights in India. As long as the windows are glass, or transparent to radio-frequency waves, the GPS signal will diffract in, as the wavelength is much larger than the size of the window. However, there are probably issues like reflections within the cabin, how many satellites are visible from the window, etc. Regards, Gora _______________________________________________ talk mailing list talk@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk