[time-nuts] Cell timing error

Dennis Ferguson dennis.c.ferguson at gmail.com
Sun Dec 16 01:04:13 UTC 2012


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 , lists at lazygranch.com 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" <jorsak at nc.rr.com>
> Sender: time-nuts-bounces at febo.com
> Date: Sat, 15 Dec 2012 18:24:20 
> To: Discussion of precise time and frequency measurement<time-nuts at febo.com>
> Reply-To: Discussion of precise time and frequency measurement
> 	<time-nuts at febo.com>
> 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" <jimlux at earthlink.net>
> To: "Discussion of precise time and frequency measurement" 
> <time-nuts at febo.com>
> 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 <timenut at austin.rr.com> 
>>> 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 -- time-nuts at febo.com
>> To unsubscribe, go to 
>> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
>> and follow the instructions there.
>> 
> 
> 
> 
> _______________________________________________
> time-nuts mailing list -- time-nuts at febo.com
> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> and follow the instructions there.
> _______________________________________________
> time-nuts mailing list -- time-nuts at febo.com
> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> and follow the instructions there.




More information about the time-nuts mailing list