Archived posting to the Leica Users Group, 2001/10/04
[Author Prev] [Author Next] [Thread Prev] [Thread Next] [Author Index] [Topic Index] [Home] [Search]Yes, we in the states use GSM. PacBell (Cingular Wireless) for one. Carriers like Sprint use CDMA, and AT&T use TDMA. =Mark On Fri, 5 Oct 2001, Austin Franklin wrote: > > Re cellular phones and aircraft interference, let me clear up a few > > misconceptions. > > > > GSM phones perform regular location updates and send measurement reports > > back to the system using a crazy burst of signals at about 217Hz > > (modulated > > at the carrier freq). Any electrical apparatus with non-linear components > > (e.g. a diode) will demodulate this, and here's your interferer. > > ANY? Even if it's well shielded? > > Do we even have GSM here in the US? I'm not sure, I only have experience > with T/CDMA phones and systems. > > > And regarding the phones chewing up capacity when in the plane at > > altitude > > ... it just doesnt work like that. A phone in a high rise can be > > 'heard' by > > dozens of base stations, but it will only ever use a carrier from one of > > them when it makes a call. The system chooses the most appropriate base > > station, based on signal strength, quality and other parameters. Handing > > over between cells is not an issue either. > > > Also, the radiation pattern from base stations is aimed towards > > the ground, > > not up in the air. > > That was my understanding also... > > > I hope this confuses things. > > You never know. > > Thanks! > > -- > To unsubscribe, see http://mejac.palo-alto.ca.us/leica-users/unsub.html > - -- To unsubscribe, see http://mejac.palo-alto.ca.us/leica-users/unsub.html