Atomic or waveceptor watches are more accurate than bluetooth, unless your phone synchronizes with an atomic time source each day, however atomic signals are not available everywhere in the world so in that case bluetooth sync wins hands down, it all depends how much of an atomic radio signal (if any) is available.
Hope this helps.

 

I've had my GB-6900AA for a few days now and I've checked it against time.gov a couple of times each day. Sometimes it's dead on and other times it's been 1 second ahead but never more than that and never behind.

I wear the watch about 14 hrs. per day and I don't keep it linked to my phone the whole time. Usually link it when I'm in situations where I know I won't hear or feel my phone ring and I don't get a cell signal inside the building where I work so it's not linked for those 8 hrs. each day.

 

Thanks rcorreale, good inputs. The reason I was wondering about it, was because I don't really know how accurately my cell phone provider is "synched up" all the time, with NIST/USNO Atomic time.

My phone (iphone5 on AT&T) only shows the time to the hour:minute, and just checking the displayed time against the NIST/Atomic website, and watching for the minute to change, it seems to be **fairly** accurate, within a couple of seconds.

There is definately something much more credible, about Atomic synch.

"My watch is synched to my phone, which gets it's time from the AT&T network, and is as accurate as AT&T decides it needs to be"

VS

"My watch gets a radio signal from the US Naval Observatory and is synched with the Atomic time signal of their clock"

 

Thanks rcorreale, good inputs. The reason I was wondering about it, was because I don't really know how accurately my cell phone provider is "synched up" all the time, with NIST/USNO Atomic time.

My phone (iphone5 on AT&T) only shows the time to the hour:minute, and just checking the displayed time against the NIST/Atomic website, and watching for the minute to change, it seems to be **fairly** accurate, within a couple of seconds.

There is definately something much more credible, about Atomic synch.

"My watch is synched to my phone, which gets it's time from the AT&T network, and is as accurate as AT&T decides it needs to be"

VS

"My watch gets a radio signal from the US Naval Observatory and is synched with the Atomic time signal of their clock"

You're welcome.

I'm using an iPhone 4S also on AT&T. You can open up the clock APP on your phone and get a visual of the seconds so you'll be able to tell to the second how far off you are against atomic time and as I said, mines never been off more than 1 second and many times dead on. Personally I think that's very good.

Sent from my iPhone using Tapatalk

 

Atomic is more 'direct from the source' and better, as long as one is in the atomic clock coverage areas. The BT sync is the next best thing for those outside of the areas, but like OP said only as accurate as the network operator wants it to be.


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I use Multi-Band 6, and so far, it's coming out pretty well! I've got a perfect accuracy with my phone (I am NOT using Bluetooth), but I think bluetooth watches would come out better since it connects with your iPhone...so I would recommend using bluetooth.

 

My GB-5600AA-1JF G-Shock is linked to the "Auto Time Update" function to the G-Shock+ Bluetooth App and it's +2 seconds ahead of the atomic clock. The AT&T clock on my iPhone is definitely NOT accurate to the atomic clock and that's why my watch is +2 seconds fast.
It seems that AT&T does not use the atomic clock time conformity on their cell phone system in order to allow my Bluetooth watch to display the "correct" atomic time to the exact second. That's not good.

 

A much more direct comparison would be between atomic sync and gps timekeeping watches. A search led me a discussion where someone was complaining GPS timekeeping took his watch 0.75 seconds off compared to a radio watch, and it was a big disappointment (for him).

 

gps vs. RC "atomic" makes more sense to compare, bluetooth is meant for interacting with a smartphone, not accurate time. cell phone network time is not stable or reliable enough to trust. I wouldn't get a BT just for time syncing.

 

I'm thinking the same thing here about the cell phone network time being unstable and being unable to keep accurate time like the atomic clock. I see what you mean about Bluetooth just being good for interacting with a smartphone. If the cell phone's network time is unstable, then there is no way that the time will be accurate to the exact second to the atomic clock time. This is a good thing to know though because I never knew that there was an inaccuracy between a cell phone network's time and the atomic clock time when comparing the two. Now I know.

 

Unless your G-Shock is suffering badly from time drift, synchronizing once at night is more than suitable. But I can see the BT method useful for those who live in areas where the atomic sync signal is weak/unpredictable.

The BT technology is very cool, but I was dismayed to discover that it requires a specific phone to use it. Despite the Samsung Galaxy S4 being Android, you can't use just any Android phone to sync with the GB-6900 G-Shock. You should be able to install a service in your Android phone, regardless of make/model, and still achieve the same thing. I do wonder if it's more about a specific version of BT than anything else....

 

Unless your G-Shock is suffering badly from time drift, synchronizing once at night is more than suitable. But I can see the BT method useful for those who live in areas where the atomic sync signal is weak/unpredictable.

Funny thing is, I've got 5 Casio wave ceptors (4 multiband 6s, one a 2 band / channel (UK / Germany) one, one of them a G-Shock). I can't remember the behaviour of my G-Shock (well in fairness, it's my son's, now) but my original wave ceptor (WVA-430) actually updates 4 or 5 times a night regardless of whether the previous attempt worked or not, whereas my Lineages will attempt 5 or 6 times, but don't attempt again, if an attempt has worked.

Can't say as I get the bluetooth thing for time sync, either - my mobiles get their time sync'd from the network, and it doesn't ever appear to be that accurate.

 

I turned OFF the "Auto Time Update" and I "manually" reset the seconds on my watch with the atomic time. The end result to this is NOT good. I've noticed that my GB-5600AA has already gained +1 seconds in less than 2 hours since I set it to the atomic time. I reset the seconds again and I will be monitoring the time gain. I'm afraid that my Bluetooth G-Shock is inaccurate and that it will gain +2 to +4 seconds or more per day if it already gained +1 second in less than 2 hours. If this is the case, I'm not going to be wearing it very much and I will dedicate most of the wrist time to my other G-Shocks which are atomic solar. I just wish that the store from where I purchased my watch on Rakuten had sent me a watch that was more accurate than the one that I got.

 

I've been monitoring my GB-5600AA Bluetooth and so far it's gained +1 second in 13 hours since I reset it with the atomic clock. The specs for accuracy for this particular model is +-15 seconds per month. If mine is gaining between +1 and +1 1/2 seconds per day then it's accuracy is "off" by +30 to +45 seconds per month. The accuracy from the AT&T network clock would probably be "off" by +2 to +3 seconds per day. I don't know whether I should keep the watch turned "ON" to the "Auto Time Update" App from my iPhone or to turn this feature "OFF and just rely on the manual synchronization of my watch once a month? I currently have the "Auto Time Set" feature turned "OFF".
I'm kind of OCD with attaining timekeeping accuracy just from owning atomic watches all along. Should I let it be and not worry that my watch gains +1 to +1 1/2 seconds every 24 hours? I don't want to open up the watch to fiddle with anything inside the module and break or damage anything. The watch is brand new and I have been wearing it for only 4 days. I like the old square "heritage" looks and styling that this model mimics of the original DW5000C that Casio came out with back in 1983. I also like the Bluetooth incoming call and incoming email alert features on it. It's basically a very sharp looking watch that can withstand 200 meters of deep water and abuse from shock with all the latest technology built into it.
Does anybody else in here own the square GB-5600AA Bluetooth G-Shock and have the same seconds gain inaccuracy problem like I do?

 

Accuracy of the watch (or any watch for that matter), is NOT determined by it's accuracy of the day it was tested. There are various factors that affects accuracy, i.e. temperature, movement, position it is placed, whether it is worn or just placed in a box etc. That is why COSC certified watches command higher prices, as well as watches like Grand Seiko, even the quartz ones are rated at +/- 10 seconds a YEAR.

If you are so determined to find out its actual accuracy, I think you will need to test it over a period of time (like a month), as it may gain today, and lose it another day, giving it its monthly accuracy rating.

 

I've been wearing the watch for 24/7 for a full 4 days since I got it 4 days ago, so it's been on my wrist at whatever my body temperature is. I only take it off when I shower. I'm going to give it a week or so on my wrist to get the total average seconds gain over a 7 day period. I've tested out many of my other Casio lcd quartz watches over a 7 day period and they usually average anywhere between a +2 1/2 to +3 seconds gain per week with an overall +10 and +12 seconds gain per month.
I'm not very happy that my Bluetooth G-Shock has already gained over +1 to (+1 1/2 to +2) seconds per day for the last 4 days while its been on my wrist when the owner's manual clearly says that it's accuracy specifications are no more than +15 seconds per month. If my watch continues to gain at this current rate every day, the total gain that it will have over a 30 day period will be +30 to (+45 to +60) seconds. I wonder whether or not Casio checked the accuracy of my watch before it left the factory?

 

Every watch goes through a series of mandatory stations during production, and I'm sure one of them is a time calibration. There is a quality control process but it will have flaws and not always catch every watch. I cannot prove this as I've not seen any verification of it, but my suspicion is that with atomic sync and Bluetooth equipped watches CASIO either skips a secondary calibration check or reduces the time involved in some way. Why do this? Saves on overhead costs and those features will take care of any time drift. It doesn't mean all of them will be this way, but that there will be some units that won't get flagged that otherwise would have for a standard G-Shock. Again, this is all speculation.

Anyway, check the manual specs and if +/- 15 sec/mo is there (instead of +/- 30 sec/mo), then you've got a case. Either simply return it to the place of purchase for a refund (most places give you a chance to return within 14-30 days), or open a service case with CASIO.

 

Even though I'm not very happy about the seconds gain, I don't believe that it's worth it for me to send the watch back 10,000 miles to Japan. I purchased it for $146 US Dollars including shipping and it was the last one that the store on Rakuten had in stock for this price. I tried to buy the same exact model last week for $98 US Dollars with free shipping from SEIYA'S Japanese website, but he sold out on it and I missed out on the good deal. The other sellers on Rakuten are selling the same exact GB-5600AA G-Shock watch right now for $154 plus whatever the shipping charges are, so I'm better off just keeping the watch and living with the +30 seconds per month time gain. It's not worth it to go thru all the hassle and send the watch back to Japan nor is it worth opening up a service case with Casio and have Casio butcher a brand new watch. I'm just going to live with the +30 seconds per month time gain and try to not think about it as much as I do with my OCD.

 

There is another possible remedy... if you're up for it.

The movement for every all digital G-Shock has a trimmer screw located on the back, that is visible when you take off the shock absorber mat. This trimmer screw makes it possible to "trim" the degree of accuracy drift the watch is experiencing. I've done this successfully on a number of models I was willing to test this. You do need a very small screwdriver, magnification, and a steady hand. See "How to Adjust Accuracy of a G-Shock" for more details.

 

My tablet but not my phone are directly inline with the atomic accuracy of my rangemen. The phone is off by 1.7 seconds So I feel they both get atomic time updates too no? The phone just suffers from network delay . I'd buy the gb6900