Just to end the discussion: Doppler shift has nothing to do with radio waves. It is true only for sound waves including ultra and infra sound with the speed of 330-350 meters/sec depending on air conditions (based on this the police radar can count your speed, actually, there are many more uses for it).
On Sat, 2002-12-07 at 07:13, Jim Thompson wrote: > > I'm not sure I want to be an "authority". Just think of me as a geek > who occasionally gets it right. > > I'm hoping for in-car mesh, btw. We would all have a < $100 802.11 > transceiver in the car, with a little omni > where the cellular antenna would be for the non-geek crowd. Then you > could hit some number of cars > from the side (so the doppler shift doesn't make the radios crap out) > via somewhat more directional > antennas. > > OK, someone shoot me, I'm starting to sound like Sam Churchill. > > On Friday, Dec 6, 2002, at 18:07 US/Pacific, Kevin Lahey wrote: > > > I'm curious about using 802.11 from my car. > > > > No less an authority than Jim Thompson explained to me at BAWUG > > last night that 802.11 was useless when the two communicating > > systems had a greater than 40-mph speed differential. This is > > apparently due to the doppler shift. > > > > As he pointed out, this wouldn't be a big problem with cars driving > > past access points, but would make it tough to put a directed > > antenna pointing down the road, since the cars would close in > > on it at fairly high speeds. I guess an omni way off the side of > > the road could provide service for a reasonable distance. > > > > Could anybody expand on this for me? I have to admit that I've > > had visions dancing in my head of in-car access for quite awhile, > > and I'd hate to think that it was unlikely to work... > > > > Thanks, > > > > Kevin > > [EMAIL PROTECTED] > > -- > > general wireless list, a bawug thing <http://www.bawug.org/> > > [un]subscribe: http://lists.bawug.org/mailman/listinfo/wireless > > > > -- > general wireless list, a bawug thing <http://www.bawug.org/> > [un]subscribe: http://lists.bawug.org/mailman/listinfo/wireless -- general wireless list, a bawug thing <http://www.bawug.org/> [un]subscribe: http://lists.bawug.org/mailman/listinfo/wireless
