Hi

Under normal conditions, the Gold Codes on CDMA are synchronized to < 100 ns. It’s only when something goes wrong
that they drift out to the 10 us range. Once they get there, the transmitter needs to shut down. Unfortunately, there is no
mandatory connection between the transmitter time source for the output coding and the time reported to the phone. Yes,
that is really weird.

Bob

On Thu, 16 Mar 2017 13:16:11 -0700, you wrote:

Not to gloat, but my Android phone is always spot on.  I have a GPS time
app that shows the difference between GPS and phone time and it's always in
the tenths of a second area.

--
Gary Woods O- K2AHC  Public keys at home.earthlink.net/~garygarlic, or get 0x1D64A93D via keyserver
fingerprint =  E2 6F 50 93 7B C7 F3 CA  1F 8B 3C C0 B0 28 68 0B

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From occasional observations of my IPhone 5 using the emerald sequoia emerald time application the "within 50 milliseconds" claim seems quite reasonable to me.

Mark Spencer

There is a lot of...problematic...advice here. For instance:

Gary Woods garygarlic@earthlink.net wrote on Thu, 16 Mar 2017
at 18:09:26 -0400 in u53mcc534t4tu924pc6rpqklolf7oelkp6@4ax.com:

Notice Gary doesn't specify which brand of Android phone, much less
the specific model and carrier. This matters...a lot.

For instance, my Verizon Samsung Galaxy S7 is regularly off by 300-700ms,
and sometimes off by more than a second. A colleague's cell phone
is regularly off by about 10 seconds. On the other hand, another colleague's
Nexus {i forget what model} seems good to 10 ms.

It's not clear to me how Android phones set their own time from the
cell network, but I think the actual answer is "in many cases, not
very well."

The "ClockSync" android app will compare your phone's time to NTP,
which does a pretty decent job.
The "GPS Time" and other similar apps will compare your phone's time to
UTC as derived from your phone's GPS receiver, although I think this is
necessarily imprecise not only because of multipath but because of software
issues between the GPS receiver and the phone. handwave

I can't speak for iPhones, but for Android phones, it's really
extremely hit-or-miss, and highly variable, both between models and
even with a given phone from day to day. And if your threshold is
something like half a second, you might think your phone is always
good enough, and then have a rude awakening (I did!) when one day it's
off by >1 second.

--jhawk@mit.edu
John Hawkinson

On Thu, Mar 16, 2017 at 2:32 PM, Severin Haas severin.haas@gmx.de wrote:

It's says '8h+/-15ms' from here in California with an uncertainty (if
I guess the German correctly) of 115ms. Not sure how it's working it
out; ping's seem to be being filtered close to the final destination.
The last hop that reported was about 175ms.

Tim

There is a NTP app for the iPhone called Gorgy Atomic Timing Clock.
You can choose from about 6 different NTP servers and it has an audible tick.  It does not (can not) set the iPhone's clock.
https://itunes.apple.com/us/app/atomic-clock-gorgy-timing/id295302256?mt=8

It was free, but now is $1.99.

John K1AE Bolton, MA

-----Original Message-----
From: time-nuts [mailto:time-nuts-bounces@febo.com] On Behalf Of Bob Camp
Sent: Thursday, March 16, 2017 6:09 PM
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] Smart Phone time display accuracy...?

Hi

Under normal conditions, the Gold Codes on CDMA are synchronized to < 100 ns. It’s only when something goes wrong
that they drift out to the 10 us range. Once they get there, the transmitter needs to shut down. Unfortunately, there is no
mandatory connection between the transmitter time source for the output coding and the time reported to the phone. Yes,
that is really weird.

Bob

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"tenths of a second" is "spot on"?  No way.  That is a difference
that is perceivable to humans.

Apple claims in their spec that the iPhone when paired with a watch is
worst case within 50 milliseconds which is not really that good but is
acceptable for a watch because it is just under what most people can
notice.

On Thu, 16 Mar 2017 20:11:30 -0400, you wrote:

Sorry about that, and I should know better (In another group "FlDigi won't
work with my radio" and nothing else...).
Droid Razr M AKA Motorola XT-107 on Verizon.
I understand tenths of a second aren't time nuts worthy, but as a clock, it
ain't bad.  Unless you're measuring the arrival time of neutrinos.

--
Gary Woods AKA K2AHC- PGP key on request, or at home.earthlink.net/~garygarlic
Zone 5/4 in upstate New York, 1420' elevation. NY WO G

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