[grandcider]

Someone gave me a Seiko watch from Japan that can synchronize with Atomic Clock time signals. Unfortunately, it seems that these signals are only available in Japan, the US and Germany so it is just running as a regular quartz watch. This makes me wonder, why are atomic clocks (or their signals) only available in these three countries? How is the official time maintained in other places?

[PDLM]

There is an atomic clock maintained by the Observatory in HK, but I guess it doesn't broadcast at whatever frequency your watch is looking for... details here: http://www.hko.gov.hk/gts/time/hk_ti...nu=addbar&time

[automatic]

The "atomic clock" watches and clocks are set by radio signal sent out from a number or atomic clocks around the world. Don't know if they are only located in Japan, USA and Germany, but certain places of the world are outside of the coverage of the radio signal of the atomic clocks that send out the signals (places close to the arctic circle in Scandinavia for instance only have sporadic coverage for the signals).

[kombuchakid]

see if you can get the time from here
http://worldtimeserver.com/atomic-clock/

your watch should have a usb/ir connection to get the time off your computer.

[jgl]

Serious clock accuracy is useful only in a smallish number of applications (financial markets only need milisecond accuracy, high energy physics need much more accuracy).

These organisations will use their own methods to access accurate timesources over physical wire or cables. And they'll use more than one source to compare accuracy of timesources.

Individual human beings don't generally need that degree of accuracy on their wrists. So that Seiko watch is basically a cool geek toy- quartz itself is far more accurate than most people need in their daily lives.

Oh, and when you say the signal is only available in Germany, that's not correct. It's available throughout most of Western Europe as I've a friend who uses one of these watches in the UK.

[jgl]

From Wikipedia: "standard is a weighted average of the time kept by about 300 atomic clocks in over 50 national laboratories worldwide. Many of these are caesium atomic clocks, which are the standard by which the SI second is defined. Due to the averaging it is far more stable than any clock would be alone."

http://en.wikipedia.org/wiki/Atomic_time

[grandcider]

It's not about needing that level of accuracy. I guess the appeal is in knowing you never have to set your watch or check it against another source to make sure it's running properly. There's no USB or infra red port on this watch.

[kombuchakid]

Originally Posted by grandcider

There's no USB or infra red port on this watch.

Then how would it receive the data to adjust itself?
Yes there is something satifying about having the correct time;I run Atomic clock every monh or so and usually am about a couple of seconds off.

[grandcider]

Originally Posted by kombuchakid

Then how would it receive the data to adjust itself?
Yes there is something satifying about having the correct time;I run Atomic clock every monh or so and usually am about a couple of seconds off.

I guess it just receives the radio waves directly

[jgl]

"It's not about needing that level of accuracy. I guess the appeal is in knowing you never have to set your watch or check it against another source to make sure it's running properly."

Yes, I know. That's why I said the watch is a great geek toy (with no sarcasm! I really like these things).

However, because wristwatches don't need to be that accurate, most governments are not going to bother with making that accuracy available to their populations via radio broadcast.

If you don't have access to a daily radio sync signal, your next choice is to buy a chronometer rated quartz watch. Chronometer standards are much higher for quartz than mechanical watches, you will probably be satisfied with that level of accuracy. However, this might be a tad expensive as chronometer rated quartz watches are not common (again, not many people need them so the market is small). Standard quartz is typically quoted as +/- 3 or 5 seconds a month.

If you're going to get seriously into time accuracy, even if there was a USB connect I wouldn't trust it. That depends on your PC being accurately synched to atomic time, and then there being no measurable delay in the signal passing through the USB port (which given how flakey USB is, I wouldn't trust it).