GSM cell sites in the US have GPS because it is required to support E911 positioning. I'm not sure if it is used for anything other than this, but it doesn't have to be.
In some other parts of the world it has been considered bad taste to let the operation of telecommunications infrastructure become dependent on a facility owned by the US military, so the standards that are popular there often try to avoid that. Dennis Ferguson On 15 Dec, 2012, at 18:59 , [email protected] wrote: > I can assure you the GSM shacks have GPS timing in them. I can dig up the > photos if you want. > > -----Original Message----- > From: "Joseph Orsak" <[email protected]> > Sender: [email protected] > Date: Sat, 15 Dec 2012 18:24:20 > To: Discussion of precise time and frequency measurement<[email protected]> > Reply-To: Discussion of precise time and frequency measurement > <[email protected]> > Subject: Re: [time-nuts] Cell timing error > > AT&T uses UMTS in most areas which is a "self-synchronizing" modulation > scheme. Supposedly one of the selling points is "no dependence on GPS". All > the extra sync channels and sync messaging is a capacity hog, not a very > spectrally efficient standard in my opinion. > > About 85 maximum simultaneous voice calls in a 5Mhz UL / 5 Mhz DL > sector/carrier before it starts to fall apart. A big step backwards from > good old CDMA2000 (also just my opinion). > > But hey, you can surf the web while you talk on the same device. > > > > -Joe W4WN > > > ----- Original Message ----- > From: "Jim Lux" <[email protected]> > To: "Discussion of precise time and frequency measurement" > <[email protected]> > Sent: Saturday, December 15, 2012 5:43 PM > Subject: Re: [time-nuts] Cell timing error > > >> On 12/15/12 2:16 PM, Scott McGrath wrote: >>> In a prior life we had a CDMA timing receiver for NTP which used VZ for >>> its source >>> >>> On Dec 15, 2012, at 12:18 PM, Graham / KE9H <[email protected]> >>> wrote: >>> >>>> You should switch to Verizon. >>>> They are inherently accurate to milliseconds. >>>> Sub micro-seconds inside the base stations. >>>> >>>> >>>> On 12/15/2012 12:51 PM, Greg Troxel wrote: >>>>> In central mass, AT&T and tracfone (? carrier) are showing phone times >>>>> very close to 1 min slow. Virgin/sprint is ok. I've never seen this >>>>> before - usually it's a few s slow. >>>>> >> >> >> The time *displayed* on the phone might not reflect the time from the >> network. >> >> _______________________________________________ >> time-nuts mailing list -- [email protected] >> To unsubscribe, go to >> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >> and follow the instructions there. >> > > > > _______________________________________________ > time-nuts mailing list -- [email protected] > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > _______________________________________________ > time-nuts mailing list -- [email protected] > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
