RHF wrote:

On Jan 20, 7:19 am, (Geoffrey S. Mendelson) wrote:
John Kasupski wrote:
Note that we're probably talking errors in the amount of nanoseconds
(per second) here, certainly not errors that are going to cause
somebody to be ten minutes late for work, but for commercial or
scientific applications requiring a time reference that is related
directly to a national or international reference, GPS may not
necessarily cut the mustard.

Yes, but don't loose sight of the fact that this discussion is really
about consumer items. One person metioned in a previous post that his
clock syncs three times a week, other than that, it "runs free".

So IMHO if you build a consumer device that syncs every 5 minutes to
a GPS or GPS based standard, it will be a lot more accurate than
the average one that syncs every 2-3 days to a radio signal.

If it were to sync every minute to a time signal inserted in a cellular
control channel, it be even more accurate. Last I checked, the AT&T
Wireless 850mHz GSM (whatever name it is called now) network covers 98%
of the surface area of the U.S.

Since it is a receiver it can be broadbanded and if it were to cover
the GSM 850/900 mHz and 1800/1900 mHz bands it would work everywhere
there is GSM coverage. Except for Estonina and Brazil, an 850/900 mHz
receiver would be enough.

This does leave out parts of the Pacific Rim (Japan and Korea) and
some parts of Oz, but on the whole it cover almost the entire
populated earth.

Geoff.

--
Geoffrey S. Mendelson, Jerusalem, Israel N3OWJ/4X1GM
IL Voice: (07)-7424-1667 U.S. Voice: 1-215-821-1838
Visit my 'blog athttp://geoffstechno.livejournal.com/

JK & GSM,

Where Do You Find The Time "Tick-Tock" - To Argue . . .
The Finer Points of Time Down To The Nearest Second ? )

And the Reality -is- for most Non-Techincal Consumers of Time :
Time that 'is' "Accurate to the Nearest Minute" is Good Enough.

=SO= For Them - Any Time In-Accuracy Less-Than 31 Seconds :
Is To The Nearest Minute. -and- That Is Good Enough For Me ~ RHF

David is Right : An Atomic Clock that resets itself a few times a
Week and uses a single set of Batterys {runs independently} that
Lasts for a Year of more : Meets the Needs of Non-Techincal
Consumers of Time.

-But- Then Again - Any common Consumer Product that has
a Time Display and is "Accurate to the Nearest Minute" also
Meets the Needs of Non-Techincal Consumers of Time.

Heck, I remember when folks were making fun of my big GMT clock here in the
shack, but it keeps on a rockin' and a tick-tock'in, and has been for almost 25
years now. Put in a new battery once a year, set it to WWV every few weeks and
that's good enough for me!

dxAce
Michigan
USA