Interesting Find: Auto DST in GW-3000B

[bluebunny63]

Found something interesting in my new GW-3000B (Module 5121): at least in the USA, it sets Daylight Savings Time (DST) to "on" when it synchs within the four continental USA time zones.

Here's the situation: I'm in Arizona, where it's MST year-round (except for the Navajos).

1. Set my home city to Denver (DEN).
2. Set DST to off (the indicator says STD, meaning standard time).
3. Returned to normal mode, and everything is kosher.
4. Let the watch synch overnight.
5. Next morning, watch is an hour ahead, and when I display my home time zone, it still shows it as Denver, but with DST "on".
6. Checked the synch indicator, and it says "Y" (Yes, I synched).

So... I figured I made a mistake with the home time zone, so I tried it again. Very carefully following the manual.

Next morning, guess what? Denver is magically set to DST "on" again. Tried this two nights running, with the same results.

Conclusion?
The GW-3000B has an undocumented auto-DST feature. Only thing that I could find supporting this in the manual was this cryptic entry: "As of November 2009, China does not use Daylight Savings Time (DST). If China does go to the Daylight Saving Time system in the future, some functions of this watch may no longer operate correctly." In other words, there is an automatic DST setting for certain time zones, and China is not currently one of them (implying that other zones, namely North America and maybe Europe, are).

I'm posting this for the benefit of others in non-DST locations (AZ, IN), who might otherwise be scratching their heads, thinking that they did something wrong by setting their watch to the correct time zone, overriding DST, and then finding the watch an hour off after a successful synch.

Personally, I'd rather Casio left well enough alone, and allowed an override of DST for every time zone, but there you have it. My fix for the thing, of course, is to simply set my home city to LAX for Summer, and DEN for Winter... oh how I wish they had an AZ zone on their watches. ;)

[jmathis]

I wonder if the same result would be for Hawaii. Hawaii does not switch to DST, either. Always HST, Hawaii-Aleutian Standard Time (UTC -10 hrs).
I'd definitely be interested in the automatic radio time-reception of the CASIO G-shock all-analog watch when in Hawaii. My Riseman GW-9200 sometimes syncs to the radio time. I'm keen for the Giez GS-1150 or GS-1400, and with your auto-DST report for the GW-3000B, I wonder if the Giez would be plagued by the same auto DST offset whenever it sync'd. I wonder if there is an equivalent UTC -11 hrs zone on the Giez, so to set the watch one hour back, as you do to West Coast time when AZ stays doesn't move to DST? I like the Giez a lot, and I never ever considered this situation. Thanks, bluebunny63, for calling this "feature" to my attention.

[sidecross]

I have three of these watches and you have to press 'button B' to switch from 'standard' to 'day light savings' when setting 'Home Time'; it is not automatic.

[bluebunny63]

I have three of these watches and you have to press 'button B' to switch from 'standard' to 'day light savings' when setting 'Home Time'; it is not automatic.

Hi Cross,

That's what I did, too. And yet, as I described above, it reset itself to DST on, even though I had set it to off. My only thought is that since I've got Pacific, Central and Eastern set to DST on, the watch assumes that having DST off with Mountain is an error.

It's a bit of mystery to me still.

[c double j]

i too have found something interesting. In my black/red gx56, if you press adjust, mode, and search all at once it lights up everything that could be readable including rcvd. i know that stands for a received time calibration. whats strange though is that this is not an atomic model because its not a gxw56. anyone reply if you have an answer

[Lexxorcist]

Sounds like they might be using the same display in the atomic and non atomic versions.

[sidecross]

Hi Cross,

That's what I did, too. And yet, as I described above, it reset itself to DST on, even though I had set it to off. My only thought is that since I've got Pacific, Central and Eastern set to DST on, the watch assumes that having DST off with Mountain is an error.

It's a bit of mystery to me still.

I better understand what you wrote.

I set my world time to UTC and I have not experienced what you have.

I have no idea why this might be happening.

[sidecross]

If anyone finds the cause of this problem, please give us the information.

[Wally79]

If anyone finds the cause of this problem, please give us the information.

The cause is that the watch module follows the time signal's dst information (starting, on, ending, off) WWV (radio station) - Wikipedia, the free encyclopedia

Some watch modules use the time signal dst info and others don't

[sidecross]

The cause is that the watch module follows the time signal's dst information (starting, on, ending, off) WWV (radio station) - Wikipedia, the free encyclopedia

Some watch modules use the time signal dst info and others don't

Thank you for this information;I put it in my favorites so I can find it again.