[time-nuts] Cell timing error

Joseph Orsak jorsak at nc.rr.com
Sat Dec 15 23:24:20 UTC 2012

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.
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