Clocks That Get GPS Time Sync

I looked at a Seiko GPS referenced clock about a year ago and decided that at $300 it didn't have anything to offer over virtually the same clock, described as "atomic" at about $40.

By the way, the Seiko's were part of a line called Space Link. Numerous versions are on eBay but most ship from Japan. Be sure you want one, as they may not work well in some buildings.

Maybe about 12 - 13 years ago I bought 2 bedside clocks/alarm clocks dirt cheap (maybe $ 5.00 ea) on clearance at some thing like Sharper Image. They are an about 5" cube. They keep accurate time by the atomic clock. There is a little icon on the screen like a tower sending signals and it's always pulsing!

Clock in my car gets its time by GPS... Yet, I still have to set (or unset) the DST flag. One would think car knows where's it at, and time zone in use. Apparently not.

It's always baffled me that it will change time when I enter another time zone, but you have to toggle DST on and off.

Quoting https://www.nasa.gov/feature/jpl/what-is-an-atomic-clock

"Atomic clocks are used onboard GPS satellites that orbit the Earth, but even they must be sent updates two times per day to correct the clocks' natural drift. Those updates come from more stable atomic clocks on the ground that are large (often the size of a refrigerator) and not designed to survive the physical demands of going to space."

Up to 50 times more stable than the atomic clocks on GPS satellites, NASA's Deep Space Atomic Clock is intended to be the most stable atomic clock ever flown in space. It achieves this stability by using mercury ions.

Much appreciated.

2006 car seems to get its time from gps. Not to be confused with XM radio. Why because I replaced the XM antenna when it went bad and it had zero effect on AM/FM/navigation/time (learned all about FAKRA connectors, it's always a journey when your stuff is old).

Also funny is its navigation system is very palm piloty/cheesy. And its calendar happened to run out 12/31/22. Guess auto designers never think a person will drive a car 20+ years or a million miles, it just happens.

Also funny and I have mentioned it, home as programmed in the gps, is the original owner's home in FLA. Car started its life in a house with an 8 car garage, and now it sits outside 24/7/365 lol

GPS satellites do not correct their clocks for leap seconds so it's necessary for a GPS-UTC offset to be applied. Currently, the offset is 18 seconds:

https://timetoolsltd.com/gps/what-is-gps-time/

Some older GPS receivers had issues with applying the correct offset.

There's a site offering the various systems' current "time":

http://leapsecond.com/java/gpsclock.htm

At GPS synchronized clocks recently when my bedside alarm clock bit the dust. They are available but a bit pricey. It is also difficult to find one that suits every need. Projector, large digit, dual alarm, alternating time & temp display, etc. are hard, if not impossible to find right now.

Unfortunately, I had to settle for a WWVB synchronized model which rarely receives the signal. I'm located too far from the WWVB transmitter in Fort Collins CO. I only get a successful update once a week or so. Some WWVB models have an external antenna jack but I couldn't find a clock with the features I want that has this jack.

Congress is also debating the shutdown of WWVB for budgetary reasons. The school of thought is, it has been made obsolete by GPS time. No date has been set though. This would be unfortunate since it would render all existing WWVB clocks useless. the propagation of the low frequency WWVB 60KHZ signal gets into places that a GPS signal can't reach.

I have been a dedicated user of WWVB clocks and watches for decades. If Congress pulls the plug I shall be particularly annoyed at losing the use of my watch. It makes power from ambient light, so I never change a battery, wind it, or set the time, I just put it on in the morning it has the right time.

WWVB comes in just fine here in Virginia.

Sharper Image has atomic clocks for under $100

I have several clocks here in Philadelphia and all can synch without any issues. I do have one very old Radio Shack clock that will not synch during the day but a reset at night forces a synch and from then on it is OK. In that regard, NIST suggests that if you can force a synch in some manner, do so at a time where it is darkness at both your location and Ft. Collins CO.

If I'm not mistaken, the Atomic Clock brand clocks are programmed to begin trying ro synch at 00:00 local time.

Like several of you, I also have some "atomic" clocks and watches with the watches being solar-powered. So nice.

I had no problem syncing them living in northern Arizona, but now I'm in a high-rise steel/concrete building in Wisconsin, and my windows face northeast. All of mine try to sync daily first at 1AM, and continue once each hour up to 4 AM until successful. They will sync but I need to place them on a window sill to receive the signal. But then, the window sill is also the place the watches want to be to recharge on bright days.

I now see that Casio Oceanus watches, besides offering WWVB time syncing, can be had that also offer "cell phone Bluetooth" syncing besides the WWVB; and also now, some that offer GPS syncing along with WWVB.

I haven't tried any but I've seen LaCrosse Technology now offers atomic clocks they call "UltraAtomic" which can receive the WWVB signals where the old "atomic" clocks can't.

https://www.lacrossetechnology.com/pages/atomic-time

I have both a LaCrosse and a TempMinder Weather Station and both have
the clock that syncs to the Atomic Clock. The only problem that I have is that it is impossible to sync in a high rise apartment, that has reinforced steel walls and steel studs.

Unfortunately, I think I face the wrong way to sync from the balcony.

I have to take it out to the lawn, under battery power to get it to sync.

I had my first Casio G-Shock Solar Atomic watch for at least a dozen year, probably more. It finally stopped working a few months ago.

I replaced it with another Casio G-Shock solar atomic watch. This new one seems to get the WWVB sync in places that the old one didn't. I have speculated this it is a more sensitive receiver, but I am just shooting from the hip on that!

It will be interesting to see is "cell phone Bluetooth" syncing comes to clocks, too.

As far as I can see, the UltrAtomic clocks are limited now to a large wall clock in two finishes.

My weather station is an Ambient Weather model. It is WiFi connected so it can publish on Weather Underground. It knows my location coordinates (part of the initial setup) and I think it synchronizes time over the Internet using nist.gov rather than via the WWVB atomic clock signal although I am not sure of that. In any case, I have never had to tinker with the time on it since I initially installed it almost 2 years ago and the time is always spot on. The console is near a window though (facing SW), so it could probably receive the WWVB signal with no problem if that is how it does it.

The Amazon Echo Show models which have an LCD screen, sync automatically via their internet connection. If you set the location, they also adjust automatically for DST. Comparing with my WWV receiving Citizen and Casio watches, the Echo Show devices are very accurate.

I have a Lenovo Smart Clock that is similar.

There are pros and cons about the use of the internet to acquire high accuracy time via some connected device. One consideration is what is called latency and depending on your bandwidth it can cause errors of 0.1 to 0.2 second at any given time.

You can read more about the various factors affecting internet time at https://www.galsys.co.uk/news/ntp-servers-versus-internet-ti....

If you want to display time based on NIST you can go to the link at https://www.time.gov/.

I just checked. My Fitbit watch is about 3-4 seconds behind and my cell phone about 1 second.

I have nothing except my OCD, that needs to be more accurate.

Thanks for the info John from PA

I don't know what is actually done but recent latency can be computed by a set of pings.

I have a 2018 Chevy , I think I have it, I've never had to set my clock or adjust it in the 5 years.

For most of the clocks I own, I'm willing to accept any minor discrepancies between these time sources. I'm more concerned that they are self regulating and that I don't have to reset them for minor drift or twice each year for the ST / DST shift.