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I did a video test last month using my panasonic dv recorder
it works like this: i make a 1 minute film of my "Thecitizen" alongside with my junghans digital watch(radiocontrolled and updated).The film is transferred to my harddiskrecorder,i then use my frame button that moves 25 frames each 1 second(tested several times to be correct).I then count the frames that the junghans is behind my citizen(the frames before the junghans cathes up to the same secondcount).
Last month it was 4 frames,as 25 frames is 1 sec, 4 frames is approx. 1/6 sec,which made me estimate 2 sec ahead/year for my citizen(good enough for me).
To my surprise this WAS NOT doubled after 2 month ,my citizen is 6 frames ahead,which is 1/4 sec ahead,estimation is the 1½ sec ahead/year?
This is very fine,though i cant understand it has not doubled,as i wear my watch 24/7 ,and not much change in sorrounding temperature?
Ill get back with a test after 3 month using my dv camera!
 

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I did a video test last month using my panasonic dv recorder
it works like this: i make a 1 minute film of my "Thecitizen" alongside with my junghans digital watch(radiocontrolled and updated).The film is transferred to my harddiskrecorder,i then use my frame button that moves 25 frames each 1 second(tested several times to be correct).I then count the frames that the junghans is behind my citizen(the frames before the junghans cathes up to the same secondcount).
Last month it was 4 frames,as 25 frames is 1 sec, 4 frames is approx. 1/6 sec,which made me estimate 2 sec ahead/year for my citizen(good enough for me).
To my surprise this WAS NOT doubled after 2 month ,my citizen is 6 frames ahead,which is 1/4 sec ahead,estimation is the 1½ sec ahead/year?
This is very fine,though i cant understand it has not doubled,as i wear my watch 24/7 ,and not much change in sorrounding temperature?
Ill get back with a test after 3 month using my dv camera!
Hi retep,

First, let me congratulate you on the excellent performance of your watch. Second, that's an excellent method you've developed. On the whole, I'd say that the variation you saw is well within what I'd expect.
 

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Excellent results, congratulations!
Though we have a fairly good understanding about the ETA Thermolines' thermocompensation scheme and we have good reason to believe that Citizen might employ very similar technology in their The Citizen, there are some areas where things are not that clear. For example your accuracy results in the past months. My Longines Flagship VHP had similar results for the first couple of months. It started like almost +0.5 second per months and then about +0.2 per months then finally it settled for almost 0 second per months and eventually after 12 months it was within the +1 second per year mark. Bruce also experienced some variations (very minor but measurable) with his The Citizen though his watch was basically spot on dead accurate after 12 months. Sometimes I had a feeling that the scheme involves some sort of "long term assessment" and adjustments apart from the regular "check and adjust in every 8 minutes" (ETA Thermolines). I admit that it is very unlikely that my speculation is correct about the "long term assessment" but I could not come up with a better explanation. Perhaps, Bruce with his engineering background can have a much more realistic explanation of this phenomenon.
 

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Bruce also experienced some variations (very minor but measurable) with his The Citizen though his watch was basically spot on dead accurate after 12 months. Sometimes I had a feeling that the scheme involves some sort of "long term assessment" and adjustments apart from the regular "check and adjust in every 8 minutes" (ETA Thermolines). I admit that it is very unlikely that my speculation is correct about the "long term assessment" but I could not come up with a better explanation. Perhaps, Bruce with his engineering background can have a much more realistic explanation of this phenomenon.
Yes, I saw these variations in rate. Mine had actually lost almost a full second after a year. (I was able to photograph twelve months of being spot on, but it was nip and tuck that last month.) If the rate I had seen in the first few months had continued, then I'd say that it would have been two seconds behind after a year.

I'm thinking that the deliberate auto-adjustment of rate over months is very unlikely. Variations happen for reasons I'll speculate on below. All else being equal, they have a roughly 50/50 chance of making things better or making things worse. The fact that we've had a few make things better may make it feel like there was a guiding influence (hmmm... decidedly theological sounding :-D ), but in reality these changes are easily explainable by random chance.

The cause of the rate changes we've noted is either small residual sensitivity to temperature combined with a varying temperature environment, or is just the next level of effects usually considered to be negligible making themselves felt. For the latter, it could be that a few molecules wafted onto or off of the crystal, changing its natural frequency. Could be a very small aging of key electronic components. At some level, there will always be variation and noise. The Shortt free pendulum regulators, famous as the most constant pendulum clocks ever made, would suffer similar extremely small but sustained shifts in rate after running incredibly constantly for months.
 

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Can I throw some fuel on the fire?

I have been thinking about something for awhile and this is a good thread to post. I have a B-1, about 7.5 yrs old. I wear it mostly on the weekends and traveling. It is about 30 sec. down from the first of the year when I synced it to the atomic clock. My thoughts/question arise from my use of the watch. During the middle part of the summer, I work it extensively because I was on the road a lot. The watch gained about 10 sec during this time. My question are quartz watches affected by our wearing them? I know this is true for auto's but a bit surprised to think that wearing, body heat, etc would have an effect.

Comments?

Thanks,
Tom V.
 

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Re: Can I throw some fuel on the fire?

... My question are quartz watches affected by our wearing them? I know this is true for auto's but a bit surprised to think that wearing, body heat, etc would have an effect...
Yes, quartz watches are affected by the changes of temperature. Over the years watch manufacturers developed different thermocompensation schemes to minimize the effect of temperature changes.
 

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Re: Can I throw some fuel on the fire?

Yes, quartz watches are affected by the changes of temperature. Over the years watch manufacturers developed different thermocompensation schemes to minimize the effect of temperature changes.
Absolutely. Change in temperature is the biggest reason that rate will change. Temperature changes can be caused by a change in the ambient temperature, or by wearing it more or less. (Wearing it puts it in intimate contact with a well-above-room-temperature object: you.) This is one of the reasons that your average quartz watch is spec'ed no more tightly than fifteen seconds a month. (The other reason is that the rate may have been set imperfectly.) Quartz watches are still way better than mechanicals in terms of rate constancy, but, as with all things, they have their limits.

A very small subset of quartz watches are designed so that this temperature dependence is largely eliminated. These are called "thermocompensated" watches. With seconds-per-year performance, they're the most precise standalone watches ever made. Check out the first sticky in this forum for an in depth discussion of temperature effects and how they're eliminated. Then let us know if you've caught the bug and need to get one of these beasts. :-D
 

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I suspect that the most important effect of wearing a quartz watch, whether compensateds or not, is the "thermostat" effect of being in constant contact with the wearer's ore or less constant (hopefully) temperature. Unless external temperature variations are really serious, I would think that they don't influence the internal temp of a watch enough. Agree, disagree, comments???
Do you think it is temperature variations, daily or periodic, or different fixed temperatures that make more difference? In other words, which would be more influential, random wearing patterns or being kept in a cold room versus being kept in a warm room?
 

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I suspect that the most important effect of wearing a quartz watch, whether compensateds or not, is the "thermostat" effect of being in constant contact with the wearer's ore or less constant (hopefully) temperature. Unless external temperature variations are really serious, I would think that they don't influence the internal temp of a watch enough. Agree, disagree, comments???
Do you think it is temperature variations, daily or periodic, or different fixed temperatures that make more difference? In other words, which would be more influential, random wearing patterns or being kept in a cold room versus being kept in a warm room?
In theory, keeping the watch in an environment with fixed temperature would eliminate the need for thermocompensation... provided that the rate of the oscillator is matched to the temperature!!! It is known as "Oven Controlled Crystal Oscillator" (OCXO) and used when high precision is paramount (eg: laboratory).
Watch manufacturers usually set the rate of their watches so that they perform best at around 25 degree of Celsius. That is about the temperature when the watch is on the wrist. So by wearing the watch all the time makes the temperature variations less severe and at the same time keeps the watch close to the desired temperature.
 

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I suspect that the most important effect of wearing a quartz watch, whether compensateds or not, is the "thermostat" effect of being in constant contact with the wearer's ore or less constant (hopefully) temperature.
I sort of agree. Temperature is certainly the big cause of rate variation in a standard quartz watch. Also, wearing a watch does reduce the temperature variations that a crystal will see considerably. Therefore, without a doubt, for a non-thermocompensated watch, wearing it regularly will substantially improve the rate constancy. If I understand you as saying, though, that wearing a watch regularly is a more assured method of achieving rate constancy than having a thermocompensated watch, then I disagree. Unless you're in a very constant temperature environment (day and night), even if you're wearing your watch, the watch temperature will vary at least a few degrees C. Also, most people don't wear their watches while sleeping, so that will constitute a significant change in temp. right there. Finally, few people have unvarying environments and unvarying wearing habits. The thermocomp. makes the watch largely insensitive to all of this.

Unless external temperature variations are really serious, I would think that they don't influence the internal temp of a watch enough. Agree, disagree, comments???
I used to think that. My logic was based on the notion that the watch is in intimate thermal contact with you, but was in much less intimate thermal contact with the air. Therefor, my thinking went, the watch is much closer to your body temp than it is to the room air temp., with corresponding insensitivity to changes in the room air temp. I've revised my thinking a bit on this though. Most watch manufacturers refer to 28C as "wrist temperature". This is actually slightly closer to typical ambient temperature (22C) than it is to body temperature (37C). Therefore, ambient seems to be at least an equal player in determining temperature. (This, of course, will vary based on the situation. If, for example, you wear your watch very loosely, and it's exposed to an open breeze so that insulating boundary layers of air are made thinner, then the watch will be much closer to ambient temp than your body temp. The opposite would probably be true for a tightly clamped watch under a shirt sleeve.) Bottom line: the manufacturers seem to think that the watch will be roughly mid way between body and ambient, meaning that ambient air temp. influences the watch (and more importantly the crystal) temperature equally. I could believe this. While the watch is in better thermal contact with your skin, it has more surface area (top and sides) in contact with the air.

Do you think it is temperature variations, daily or periodic, or different fixed temperatures that make more difference? In other words, which would be more influential, random wearing patterns or being kept in a cold room versus being kept in a warm room?
I would say the latter. Random wearing patterns will tend to even out their effects over time. (There's divergence due to random walk, but that's a bit technical.) Being in a cold vs. hot room will lead to a net, cumulative effect.
 

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To answer Mr Reding's implied question, No I didn't mean that I thought wearing a watch was better than, or as good as, having thermal compensation. And I agree that the thermostat effect of constantly wearing it will vary with whether you wear it snug or flopping like a bangle. And it certainly seems reasonable that both body temp and ambient temp will play a part in the degree to which the watch's internal temperature will vary. Maybe we need to find transparent, insulated wrist guards to maintain as level a temperature as possible!
 
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