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Atomic Clock - Wrong Time

06/02/2014 3:25 AM

I've got one for you. I have owned a SioScan Atomic Clock for years. It's been very accurate and I've never had to do anything, except change batteries.

In the fall of last year, we changed to daylight savings time, but the clock didn't automatically change. I tried to manually change it - it worked okay until the next morning. The clock must have sync'd with the Atomic Clock and it went back to one hour off. After two more days of this, I did what any practical engineer would do - I turned it around, so I couldn't see the time.

This spring, I thought it would re-set to non-daylight savings time and would display the correct time. Unfortunately, it's still one hour behind. Does anyone know if there was some change to the Atomic Clock signal and I'm not getting the correct signal. I'm here in Los Angeles County, CA - not sure if that has anything to do with it.

This one has me puzzled!

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#1

Re: Atomic Clock - wrong time

06/02/2014 3:58 AM

These 'atomic' clocks (radio clocks, more accurately) depend on shortwave broadcasts of time signals. Shortwave frequencies are capable of notoriously long range. There are other time-signal stations around the world. It is quite possible that a new station has come online somewhere, one whose signal strength at your location surpasses the signal from WWV in Fort Collins, Colorado. Your being near the west coast/Pacific Ocean suggests that the 'new signal' is coming from somewhere offshore. As seawater is more conducive to extending the range of shortwave broadcasts than land, chances are pretty good that the signal is originating offshore. Mind you, all of this is speculation. On the other hand ...

NIST also operates a time-signal station, WWVH, in Kekaha, Hawaii. Hawaii does not observe Daylight Savings Time - and neither does your clock. Possibly WWVH upgraded their transmitter recently?

On the flip side, your clock may be designed to receive a low-frequency broadcast. WWVB in Fort Collins broadcasts on 60 kHz at 70 kW. Japan also transmits a time signal on this frequency (as does Russia and the UK) and broadcasts at 50 kW ERP. Thing is, they may all use a different time code.

While most time signals encode the local time of the broadcasting nation, the United States spans multiple time zones, so WWVB broadcasts the time in Coordinated Universal Time (UTC). Radio-controlled clocks can then apply time zone and daylight saving time offsets as needed to display local time

LF transmissions have extremely long range and are less affected by ionospheric anomalies, making the lower frequencies more reliable. It is possible you are receiving Japan's transmissions?

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#5
In reply to #1

Re: Atomic Clock - wrong time

06/02/2014 7:16 AM

UTC does not observe Daylight Savings Time nor does WWV broadcast local time, only UTC.

UTC is simply the time at the Greenwich meridian. So, competing stations would not transmit different time stamps, although there may be some propagation delays, it would not be one hour off.

If I were to hazard a guess it would be that the radio has a mechanical switch that allows the user to select for DST or not, depending on where they live. The contacts on that switch may be oxidized or a fault with the trace to the microprocessor may be the cause.

Flipping the switch back and forth several times or better yet, applying some contact cleaner to the switch may resolve the problem.

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#13
In reply to #5

Re: Atomic Clock - wrong time

06/03/2014 6:29 AM

Your answer would be correct if there was a switch for DST. My clock has a button to select the deviation from GMT (+_ hours from GMT). It also allow me to turn DST on and off.

My clock isn't processing the radio signal correctly.

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#18
In reply to #13

Re: Atomic Clock - wrong time

06/03/2014 7:23 AM

Is there a visual cue that tells you that DST is ON or OFF?

I would be looking to see if the clock was responding to user input with that switch.

I am not sure where you are at, but make sure that you have the correct number of hours offset from UCT.

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#19
In reply to #13

Re: Atomic Clock - wrong time

06/03/2014 8:01 AM

Did you try changing the offset by an hour? Since DST is dependant on both the dateand the political entity you reside in (not every location uses dst) then the clock would need to know both the current date, as well as whether DST is observed in your locality. on top of that congress changed the start and end dates of DST in the US a couple years ago, and if the clock is older than that it won't know anything about that change. My solution would be to advance the offset manually for DST.

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#2

Re: Atomic Clock - wrong time

06/02/2014 4:19 AM

On some clocks there is a switch that lets you select your time zone, but the change from/to daylight savings time may have to be manually regulated, because even though you may be located in certain time-zone, not all states within that time-zone will necessarily recognize daylight/standard time. Unless your clock has a table of which states do and don't - and unless your clock 'knows' where it is, it is likely you'll have to change it manually.

How does your clock know it's in California? It could only know one of two ways: it contains a GPS receiver which tells it where it is, or you do.

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#3

Re: Atomic Clock - wrong time

06/02/2014 4:34 AM

This may something of note. From NIST:

"Since October 29, 2012 at 1500 UTC (9:00 AM MDT), NIST Radio Station WWVB has been broadcasting a phase modulated (PM) time code that has been added to the legacy AM/pulse-width-modulation signal...

... Disciplined oscillator products that track and lock to the 60 kHz WWVB carrier and were designed to work as frequency standards, will not work with the PM [phase-modulated -ed] signal and have become obsolete. Radio-controlled clocks that are based on synchronous AM demodulation (lock to the carrier), such as the Spectracom NetClock and receivers manufactured by True Time during the 1970s and 1980s, have also become obsolete."

Does this coincide with the problem with your clock?

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#14
In reply to #3

Re: Atomic Clock - wrong time

06/03/2014 6:31 AM

Mine worked okay until the DST change last fall. I believe it's picking up the signal, because I can manually change the time, but when it syncs up at night, it goes back to the wrong time.

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#4

Re: Atomic Clock - wrong time

06/02/2014 4:47 AM

1. Take the battery out of the clock.

2. Press the manual time setting tab on the back of the clock 15 times.

3. Put the battery back into the clock.

4. The clock will go to 4:00, 8:00, or 12:00 and stay there while waiting for the signal.

5. Immediately after your clock stops at 4:00, 8:00, or 12:00, push and hold the manual time set tab until you get to the correct time. If you release the button at the incorrect time, take the battery out and start again.

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#15
In reply to #4

Re: Atomic Clock - wrong time

06/03/2014 6:34 AM

Good find, but I did this already.

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#6

Re: Atomic Clock - wrong time

06/02/2014 8:22 AM

I have had two watches that pick up the WWVB 60kHz signal, and they automatically set to the correct time for daylight savings time. As others have suggested, check to see if there is a switch on your clock to disable daylight savings time for folks that live where they don't observe it.

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#9
In reply to #6

Re: Atomic Clock - wrong time

06/02/2014 10:06 AM

You are correct, while WWV and WWVH still broadcast on 2.5,5,10, 15 and 20 MHz. the one most used is 60 KHz.

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#17
In reply to #6

Re: Atomic Clock - wrong time

06/03/2014 6:37 AM

My clock has the DST setting and here in CA we have DST, so it's on. Time shows 2:36 am, when it's really 3:36 am. What am I still doing up? Good night everyone!

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#7

Re: Atomic Clock - Wrong Time

06/02/2014 9:20 AM

I don't recall the details but quite a few years ago someone (Bush 43?) changed when Daylight Savings Time started and ended. If you are off by one hour just after a change then I wonder if your clock has a DST change table that conforms to the old standard.

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#8
In reply to #7

Re: Atomic Clock - Wrong Time

06/02/2014 9:39 AM

WWV transmits a digital code for encoding the state of leap seconds and DST in the digital time code. So, if DST start/stop dates change, WWV will broadcast that change.

It's up to the user to either enable or disable DST recognition on their clocks.

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#10

Re: Atomic Clock - Wrong Time

06/02/2014 8:51 PM

SkyScan Atomic Clocks | Customer Support & Service
I've got an Oregon Scientific mini weather station that has never recognized DST.I live in AZ and we don't either. I just tell the clock we live in CA and it's happy.

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#20
In reply to #10

Re: Atomic Clock - Wrong Time

06/03/2014 3:20 PM

"Does anybody really know what time it is....?"

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#11

Re: Atomic Clock - Wrong Time

06/03/2014 4:52 AM

Back to clockwork for me. My radio controlled watch went exactly 30 mins out. It changes with the summertime settings etc but is always exactly 30 mins out. I've tried resetting it but to no avail. I have a solution that involves taking the back off .....

On the subject of timekeeping in the UK we have the pips. On the hour the BBC give out an accurate time signal which is a series of pips followed by a long one which is the time marker. With modern technology - digital radios etc the time signal is way out when compared against an old AM or FM radio.

Clockwork - it rocks!

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#12
In reply to #11

Re: Atomic Clock - Wrong Time

06/03/2014 5:36 AM

A possible further help to your post further (and that of Solar Eagle too!) is to remove the batteries, press and hold any and all switches.

Put a short across the battery input terminals on the unit (naturally with no batteries installed!) for at least a few seconds, to discharge any charged up caps.

Leave it for at least 24 hours with no batteries/power.

Put the batteries back in again and see if it works as it should.....

I have over very many years brought back to life many electronic devices in this manner. It is nowhere near to being a full 100% effective, but its a simple trick that anyone can try out.

Either it works or it doesn't....

I have posted this before somewhere on CR4.

It is not a secret, many know and use this method first of all, to reset modern electronics.....

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#16
In reply to #12

Re: Atomic Clock - Wrong Time

06/03/2014 6:36 AM

Good idea. I'll do this and let you know if it works. I did try the method Solar Eagle posted and it didn't work. Maybe I need to do a complete reset.

I'll let you guys know if it works.

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#22
In reply to #12

Re: Atomic Clock - Wrong Time

06/04/2014 2:21 PM

It worked perfect. There must've been a charged capacitor in the circuit. The odd thing is when I remove the batteries, the unit would default to 12:00 and all settings would be cleared. I thought that would be enough to reset the DST function - that's where I think the error was coming from.

Anyway, it works perfect now. Thanks for the answer!

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#23
In reply to #22

Re: Atomic Clock - Wrong Time

06/04/2014 5:52 PM

Its a nice trick, that works probably more than 50% of the time, though I haven't really counted the percentage.

Funnily enough, I fixed an HP printer for a friend of mine today, that would not use black ink anymore....

I am pleased that I was able to help you.....

Exactly WHY it works I can only guess at, so here goes, my guess is that the processor has been badly programmed, and there is a "one way street" with no way out in the code. A situation that the programmer never dreamed could happen.....

Powering off FULLY, allows the code to run clean again/start afresh.....of course this could also mean that the code could error again in a few years time, sadly...

Hopefully not!! But at least you know the fix!

By the way, some devices need several days of no power by the way, so don't ever give up!!!

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#24
In reply to #23

Re: Atomic Clock - Wrong Time

06/04/2014 10:08 PM

I have a Mercedes C230 that won't recognize the key. The slunk noise that usually occurs when you put the key in the ignition doesn't happen and the key doesn't turn. I've done everything I can to clear the memory. I've been told that the ECM is bad. I hope not, because it's about $1K to fix it. I'm driving one of our other cars right now.

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#21

Re: Atomic Clock - Wrong Time

06/03/2014 11:09 PM

It works off of National Bureau of Standards WWV clock which doesn't do daylight savings...get your setback by changing your timezone...that worked for me.

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#25

Re: Atomic Clock - Wrong Time

11/27/2016 6:57 PM

I do believe there is something going on I have noticed it for the last two years.when it time to change the clocks the automatic one are a little ahead of all my clocks that have to be manually adjusted. This last time I made sure of this by setting four separate clock at the last time change and sure enough this time change the self adjusting clocks were a had by ten minute s and the manual all read the same time so they were not faulty. There is something!

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#26
In reply to #25

Re: Atomic Clock - Wrong Time

11/28/2016 1:04 AM

My atomic clock is 4 minutes behind. I've tried to correct it and it goes back to the 4 minute late time.

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#27
In reply to #26

Re: Atomic Clock - Wrong Time

12/02/2016 2:24 PM

Sioscan clocks set off of the National Bureau of Standards, who sets the standard for your 4 minute late time?

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#28

Re: Atomic Clock - Wrong Time

01/31/2018 10:19 PM

I love your answer! I am in Electronic Engineering as well. My clock does the very same thing, and I seriously doubt anything can be done about this issue. The suggestion to move the clock to a northern exposure defeats to point of having this clock for a visual reference of the exact time. In any case, please accept my clock and turn it around next to yours.

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#29
In reply to #28

Re: Atomic Clock - Wrong Time

02/09/2018 5:56 AM

I decided to just let my clock sit on my window sill. It at least tells the temperature, but it also doesn't seem accurate. I'm almost to the point of throwing it out ... hmmm that sounds like a good idea!

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