"Radio-controlled" clocks change time

[KK4JUG]

Sorry folks, I didn't know where else to put this.

Two of my "atomic" clocks changed time today. Both lost 2 hours. Now they have the Mountain Time. I quickly realized I don't care what time it is in Denver because I'm in west-central Georgia. Neither my Citizen watch, another wall clock nor my weather station changed time.

Is this what my next door neighbor calls a "transient anomaly"? I have to think some kind of radio signal snuck into the house for it to happen to only 2 (of 5) timepieces.

 

[jwt873]

I have two 'atomic' wall clocks as well as a watch.

Probably not related to your problem, but for the first time ever, just last week, one of the clocks started acting up. It never changed time zones, but it was out by several minutes for two days in a row. Looking closer, I noticed the low battery indicator was on. Replacing the batteries fixed it.

The time code signal broadcast by WWVB doesn't contain time zone info, so it shouldn't be able to change it. Time zone is a local clock setting much like choosing 12hr or 24 hr display format. On the WWVB page, they indicate that being out by an hour or more is most likely that the local time zone is set wrong in the clock. Help with WWVB Radio Controlled Clocks

But since two clocks went at the same time, it must have had something to do with how the clocks handled signal.. Were both clocks the same brand/model? Could be something related to the manufacturer.

FWIW I've been using WWV clocks for around 14 years and have never had the time zone change.

 

[KK4JUG]

One of clocks is a Sharp and the other is a Howard Miller. That doesn't mean they're not the same guts, though.

Both are keeping accurate time...for someone 1500 miles west, so I'm puttin' my money on a glitch in the signal

 

[KK4JUG]

Well, I'm satisfied that it was a "glitch" in the radio signal. The Sharp clock returned to the correct time this morning. The Howard Miller is still showing the 2-hour error. It may not have picked up a signal last night. I'll give it one more night before I start fiddling with it.

 

[trentbob]

Very interesting thread!!! Especially one returning to normal time and the other still has the error and others unaffected.

 

[Ubbe]

It seems that radio controlled clocks needs a better signal strenght when doing changes like DST, perhaps a more complex data telegram, compared to when just sync the time. My clocks use a german transmitter at 77KHz and keep perfect time down to the second but each time it's going to change to and from DST it doesn't do that until I move the clock to higher ground.

/Ubbe

 

[KK4JUG]

I'm pretty sure they don't all always pick up a signal every night. Some of them have an indicator to show that; some don't. Historically, they're all very accurate even after not picking up a signal for 4 or 5 days meaning I've never had a problem with any of them and don't check that signal indicator. DST has never been a problem, Ubbe.

In the grand scheme of things, this is really no big deal but it seems to be an unusual occurrence.

 

[jaspence]

I have had several of these devices since the first Casio "Pathfinder" wrist watch. Weather conditions can cause them to miss the signal. Even storms that are not close to me in Mihcigan but in the signal path can cause one watch to miss but not the other. My original one from the late 1990's is still working well and has the original strap. It is a solar powered model and also has the original battery.

 

[N9JIG]

Many of those clocks are designed to change the time zone on a specified day which would have been current at the time of manufacture. If at that time it was the "Last Sunday in February" then it would change then. WWV would only be used to determine the proper GMT time, there is a setting to set the time zone relative to GMT, so if it was set to -8 or something it would subtract that many hours from the WWV time.

With the date the time changes from Standard to Daylight changing over the years and even from country to country it is possible that your clock is set incorrectly. While some devices are updated (especially if they are connected to the Internet) some are not. Since these are sold around the world these clocks may have been set to change to Summer Time as used in the intended country but sold here instead. It could also be incorrect coding as well. I don't know if WWV/WWVB sends out a trigger for DST or not, if not then it is reliant on the device to select the change date.

I had a devil of a time when I moved to Arizona, many of my devices changed time on the correct dates for my former home but here we do not use DST so most of my stuff was off by an hour in the summer and I had to reset them. Not all devices allow a way to turn off DST.

 

[nd5y]

I don't know if WWV/WWVB sends out a trigger for DST or not, if not then it is reliant on the device to select the change date.

They do.

WWV and WWVH Digital Time Code and Broadcast Format

www.nist.gov

 

[N9WI]

Found this: Hd 1688 Sheng Bang User Manual May be useful.

 

[firemun]

My ”atomic” clock occasionally resets itself to 40 minutes (exactly) ahead of the correct time. It does this 4-5 times a year. No rhyme or reason I can find as to why. Its always good for an adrenaline rush to wake up thinking you are 40 minutes behind.

 

[KK4JUG]

You know what? Looking at the problems others have had, I'm gonna just leave mine along and count my blessings.

 

[slowmover]

My experience was with wall clocks (where mounted; signal strength). My idea was to have a household master clock.

I got over it. Getting rid of as many “controlled devices” is a better approach in life, IMO.

A Seiko 5 is good enough.