[time-nuts] Handy iPhone app

[Michael Conlen]

In Tampa bay AT&T is about 17 seconds off

--
Mike

On Jul 16, 2010, at 1:00, Peter Monta <pmonta at gmail.com> wrote:

> Oz-in-DFW writes:
> 
>>> ... There is no way AT&T would be 12.4 seconds off ...
>>> 
>> 
>> I used to work in the cell infra business.  While it's less true today,
>> there are still a number of operators that do not sync system clocks.
>> The time supplied to users can be **minutes** off.
>> 
>> Most newer operational standards can't tolerate this and "accurate" time
>> (better than a ms) is important.  WiMAX requires TDD base stations to
>> base station alignment to be better than 1 microsecond.  Most telecom
>> operators want to avoid GPS at every site. It's a logistical PITA.
> 
> Here in the Bay Area, AT&T/iPhone time has gotten noticeably worse
> recently.  The error used to be around 4 seconds; now it's 49 seconds (!).
> 
> Emerald Time is fine for interactive use, but what I find very impolite
> is that AT&T's bad timestamps are written into the EXIF headers on photos.
> Sometimes I take pictures of sundials, for example, and a 49-second
> error is not negligible for a carefully made dial.
> 
> It would be amusing to arrange for a long-term record of the offset of
> one's phone (which can of course change across multiple providers during
> travel), say by using a background process to take a sample every few hours
> against NTP sources or against GPS if the phone has it (or both).
> Then any photos can be batch-corrected later if desired.  Apple, give
> me control over the time on my own phone, and please don't force me to
> resort to these schemes :-).
> 
> Cheers,
> Peter Monta
> 
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