# Adjusting watch accuracy?



## TheBob (Jul 20, 2003)

Many years ago I bought a Timex Expedition. I'm not sure what the guaranteed accuracy was at the time, but I suspect at least 1 minute/month since I don't recall seeing anything better at the time.

Well, this thing was amazing. In the first 49 days it was no more than 1/4 second slow! After that, it gradually got faster going from a gain of 1 second in 40+ days to a gain every 3-3.5 days.

Now, I know that is still very good, but I had gotten spoiled. I wrote to Timex about adjusting it, but they said a watch that was out of spec would have to be sent back to them. Of course, mine was not actually out of spec. They also told me that all their watches were now accurate to within 15 seconds/month.

So, some months ago I bought a new one on sale in hopes that it may be better than what I had. It turns out it is a little - I'd say about 1 second every 6-8 days.

But I really want to be able to adjust a watch myself, if that is possible. You know, like maybe there is something inside I could access that allows some compensation for any flaws in the crystal's frequency. That way maybe I could take my old watch and experiment to get it to be extremely precise again.

Bob


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## Darell (Jul 20, 2003)

One day everything will be set via RF from the atomic clocks around the world. Until then, I certainly have no answer. /ubbthreads/images/graemlins/icon3.gif


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## shrap (Jul 20, 2003)

Lots of watches can set themselves from the atomic clock signals. Too bad there's only one emitter, in Colorado.

However, I can just use my cell phone, which seems to be atomic-clock corrected; or go the high-tech approach and use my GPS reciever. 

Original poster: I find it strange you need up to 1 second accuracy. I'm happy if my watches are all under 5 minutes fast.


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## vcal (Jul 20, 2003)

A very few quartz watches have a very tiny screw (close to where the battery is replaced), that is the regulator.

The way to spot it is to find a screw that has an orange or brown wide washer around it. i.e.-a screw that really wouldn't need a washer on it otherwise.

If you find such a screw, it will make the watch run faster if turned CW or slower if turned CCW.

I've seen this regulator on some quartz watches from 1980->Now, and on Texas Instruments, Timex, Lorus, etc. (digital and analog). I've Never seen it labled as such. /ubbthreads/images/graemlins/frown.gif
-found on cheap to expensive watches...

**Did'ya know: ??
*Any* quartz watch will run a little faster in cooler ambient temperatures, -and will slow a little bit from normal (say 72°F) when it's hot.

I have about 5 watches that are within 1 second per month, and use this method to "ultra-fine" regulate them. /ubbthreads/images/graemlins/grin.gif


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## Empath (Jul 20, 2003)

Some atomic watches are also programmed to adjust their timing based on its error each time it has to readjust itself. That's a great idea; I don't know why it hasn't been incorporated into other watches and clocks. The program would just need to calculate the error between settings and compensate the count from the crystal.

If you're using an analog watch, and if you don't really need the second hand, you might be able to get a watchmaker to remove the second hand for you. That way, it'll look exact for months on end, possibly only needing reset at DSL time twice a year. That's what I prefer to do to with wall clocks. If possible I remove the second hand. I don't know why the manufacturers are so persistant about second hands on clocks. It always bugs me when I look at a clock, and even though it's quartz timed, I see it a few seconds off after just setting it a few weeks earlier.


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## tiktok 22 (Jul 20, 2003)

IMHO I've always liked clocks and watches with second hands. It's the easiest way to tell if it needs wound or the battery needs replaced. /ubbthreads/images/graemlins/smile.gif


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## mattheww50 (Jul 20, 2003)

actually there are several emitters, but only one can be reliably heard in North America. Sieko actually makes a travel alarm clock that will synch to the Japanese signal (reaches about as far as Korea), the Ft. Collins Signal, the UK signal (covers UK and Ireland) and the German Signal (reaches into Scandanavia) and I can advise that it really does work)...


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## TheBob (Jul 20, 2003)

> Lots of watches can set themselves from the atomic clock signals. Too bad there's only one emitter, in Colorado. <

They won't reach me here in Hawaii. There are also ones in Europe, but even if I had a watch that worked with them, they are too far away too.

> However, I can just use my cell phone, which seems to be atomic-clock corrected; or go the high-tech approach and use my GPS reciever. <

I don't have a GPS - though I'd love one that was nice and cheap, but gave very accurate readings for altitude because I ride a bike and like to know how high I've climbed on hills.

I do use my cell phone (sprint) to check my watch, but while the phone is quite accurate, I have noted that it will fluxuate as much as 2.5 seconds. This is no problem except it makes it hard to calculate what my watch is doing when I compare since I can't be sure how much the phone is off at that particular moment. Over many days, it doesn't matter, but it takes a lot of days to get a very exact average.

> Original poster: I find it strange you need up to 1 second accuracy. I'm happy if my watches are all under 5 minutes fast. <

I don't need 1 second accuracy, but I do like things to be as accurate as possible. Barring perfection, I'd be thrilled to have a watch that I only reset once a year. It used to be twice a year, when the time changes anyway, but in Hawaii we never change. If it was off 20 seconds a year, I'd simply set it 10 seconds off one way and at the end of the year, it would be 10 seconds off the other. I'd consider that to be a meaningless difference. I guess anything within a 60 second error/year would be okay, but less is always better.

Bob


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## TheBob (Jul 20, 2003)

Thanks for that info. I'll look for such a screew today.

> Any quartz watch will run a little faster in cooler ambient temperatures, -and will slow a little bit from normal (say 72°F) when it's hot. <

> I have about 5 watches that are within 1 second per month, and use this method to "ultra-fine" regulate them. <

Yeah, I noted that on my original watch, when I replaced it with my new one, it started running a bit faster (since it wasn't heated by my arm). Unfortunately, it was already fast so that wasn't a help. My new one is also a bit fast.

Bob


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## Floating Spots (Jul 20, 2003)

As for those self setting clocks, I have a Radio Shack clock radio with this 'feature'. This one is set to sync two a day (I think at 4?). Mine, however, has had the distinct ability to misset itself, causing me to be late to work my only two times. And its not like its off by whole hours, it just sets itself to whatever it wants. So I broke down and disabled the feature.
I sure would like one that works or that confirmed with the user before it reset itself more than say 15 minutes. If it was drifting more than 15 minutes twice a day, there has to be a problem. /ubbthreads/images/graemlins/icon6.gif


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## TheBob (Jul 21, 2003)

membr123,

I checked my watch, but there is no adjustment screw. Thanks anyway.

Bob


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## shrap (Jul 21, 2003)

[ QUOTE ]
*mattheww50 said:*
actually there are several emitters, but only one can be reliably heard in North America. Sieko actually makes a travel alarm clock that will synch to the Japanese signal (reaches about as far as Korea), the Ft. Collins Signal, the UK signal (covers UK and Ireland) and the German Signal (reaches into Scandanavia) and I can advise that it really does work)... 

[/ QUOTE ]

That's cool. Are there traveler's watches that can pick up all of these signals, or are there brand- or region- specific watches only?


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## paulr (Jul 21, 2003)

CDMA cell phone time is normally sync'd to the GPS system but occasionally it goes completely out of whack. I noticed my phone was half an hour off once, and stayed that way for the better part of a day, but eventually it got straightened out.

You can get the time pretty accurately (to within a few tenths of a second) from www.time.gov with an ordinary web browser. That should be fine for setting a watch. Of course you can get much better accuracy from an NTP server or with the 1 PPS output of a GPS board. Handheld GPS receivers displaying the time can be off by as much as a few tenths of a second because of lag in the display processing.

Also note that GPS time as broadcast by the satellites doesn't take leap seconds into account. The receivers correct for that, but only after they've received a complete update from the satellite, which takes around 12 minutes. So there's some situations where you can turn on your GPS receiver and have it display the time, and it's off by 10 seconds or so for the first 12 minutes after power-up.


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## Sharp (Aug 2, 2003)

[ QUOTE ]
*Darell said:*
One day everything will be set via RF from the atomic clocks around the world. 

[/ QUOTE ]

Casio, and I think others too, have already made this.


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## hyeTotum (Aug 5, 2003)

[ QUOTE ]
*paulr said:*
You can get the time pretty accurately (to within a few tenths of a second) from www.time.gov with an ordinary web browser. That should be fine for setting a watch. 

[/ QUOTE ]

The "accuracy" figure usually improves for me by hitting *one* 'refresh'. (More than one refresh usually causes the accuracy to deteriorate.)

[ QUOTE ]
*TheBob said:*
...They won't reach me here in Hawaii...

[/ QUOTE ]

That's a shame -- what with WWVH sitting right there on Kauai! You would think they could modify the watch circuitry to accept the 'sister' station's signal?!


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## TheBob (Aug 8, 2003)

It isn't a question of picking up the basic time signal apparently. The Colorado station has a special setup that sends out code the watch picks up. Kauai doesn't do that at all.

BTW, I got a shortwave radio which I use to check accuracy. I was surprised to find that I often can't pick up any signal, not even Kauai. Considering how close I am, I didn't expect that.

Bob


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