# Bulova High Performance Quartz CURV Titanium



## Pjerome (Oct 15, 2010)

Like a fine piece of Artwork that runs amazingly and feels amazing to wear, this watch is some pretty nice engineering by Bulova. Lightweight and comfortable. Can be very dressy or sporty with jeans...Not quite ALL AMERICAN made but still well done. Don't think about changing the rubber strap. It's not happening. At least not until Bulova makes a leather that will fit. I also have the Moonwatch..and 30 other watches. These are keepers for my collection. No Quartz is better than an ACCUTRON at 10 seconds per year? . I love mechanicals but it really is nice to never have to set my watch before wearing it.


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## gangrel (Jun 25, 2015)

There are quartz watches accurate to 5 SPY.

And, the experience here has been that the 262 kHz movements don't generally perform to 10 SPY. Mind, they're really good within the overall quartz universe...30-60 SPY, IIRC, and that's fine for most of us...but Citizen, Seiko, and the Swatch brands can all point to accuracy of that level or better.

Now, I do gotta grant that the Curv in the first couple pics of yours looks pretty cool. Maybe we can ship some of their designers over to Longines............


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## Pjerome (Oct 15, 2010)

It is advertised as 10 sec/year but who really knows? Close enough. It is definitely the first and still the ONLY Curved Chronograph. It's very "Artsy " looking. Like Dali's melting watches actually."The Persistence Of Memory".


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## Hans Moleman (Sep 24, 2007)

The three pronged crystal!
Or at least a stylized image of one.


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## ronalddheld (May 5, 2005)

Time will tell how well or poorly this watch performs


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## hughesyn (Oct 9, 2014)

If 262 kHz is Ultra High Freqency, then what is 4 MHz? 
I guess Super High Frequency, since (in the world outside Bulova's marketing department) that comes above UHF.

I suppose 'Slightly Higher Frequency' wouldn't have much of a ring to it.

Love the curved movement and display back. Very Moser.


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## Hans Moleman (Sep 24, 2007)

ronalddheld said:


> Time will tell how well or poorly this watch performs


Quite unfortunate that a Bulova is even mentioned in a High Accuracy Forum.

For some that is endorsement enough.

That's the internet for ye!


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## BillSWPA (Feb 19, 2015)

I have had a 262 kHz movement for about a year now and it has never been more than 2 seconds off in that time, resetting only for daylight savings time and 1 precautionary battery change.



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## wbird (Feb 25, 2015)

ronalddheld said:


> Time will tell how well or poorly this watch performs


Couldn't you say that about any brand or watch? Therefore not really needed, but thanks for the reminder.


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## wbird (Feb 25, 2015)

Hans Moleman said:


> Quite unfortunate that a Bulova is even mentioned in a High Accuracy Forum.
> 
> For some that is endorsement enough.
> 
> That's the internet for ye!


Not sure why it's "unfortunate." Recent data on these threads, and the Bulova forum seems to show that Bulova's are performing as well if not better than most of the 3 hand PreciDrives from Certina on this forum, including mine. I have both brands, only the Bulova ever went a year at less than 10 spy.

OP nice looking watches you have there, no reason to believe they won't perform well based on recent data, and look forward to seeing your results.


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## gangrel (Jun 25, 2015)

BTW, on the "not quite ALL AMERICAN made"...is any part American at this point?


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## yankeexpress (Apr 7, 2013)

Hans Moleman said:


> Quite unfortunate that a Bulova is even mentioned in a High Accuracy Forum.


This comment is Baloney. My HAQ Certina and Precisionist, 262kHz and atomic Casio all keep time accurately as each other.

Other than TC, temperature compensation, the Bulova lacks nothing for accuracy against a HAQ.

For all practical purposes in daily use, the Bulova Curv is accurate.


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## sertse (Sep 30, 2012)

I don't know why we continue to hang Bulova for marketing claims made 7 years ago and retracted for almost 5 years. As for the Curv, the manual currently on the Bulova website officially claims it is accurate to 5 seconds/month or 60 seconds per year.

That said, I feel that is a overly conservative spec and I agree with others that 'recent' Bulovas are generally better. You could likely claim it is 'HAQ' if we used the traditional 25 second/year spec (I know TC etc but I'm generalising); I don't think anyone has claimed worse than that since the original Precisionist days. I know the industry consensus is now 10 sec or better, but imo the Bulova is a respectable watch to at least be mentioned on the forum lol.

I hope the OP would test his watch. It makes for an interesting hobby and it'll be good to have more data points.


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## ronalddheld (May 5, 2005)

For modern watches,the standard is ~10s/y.


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## DaveM (Aug 9, 2008)

IMHO Thermal Compensation is NOT a requirement for a watch to be HAQ, but thermal insensitivity is !
To be HAQ a watch must be within 10spy over a range of temperatures (say 15C to 30C).
I do not regard a watch that can only better 10spy when in a thermal-chamber as HAQ.
My understanding is that for a 32Khz tuning-fork crystal 10spy over 15/35C requires TC.
For both technical and cost reasons compensation is never 100%, so a (HF ?) crystal with better thermal insensitivity has to be a step forward.
But from posts on this forum the Bulova does not meet my spec.
Having said that if it has no-TC performance which is 'almost HAQ' it should be a no-brainer for Citizen to add TC and better the Longines VHP (poor TC of a crystal with a lot of thermal drift) !


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## ppaulusz (Feb 11, 2006)

DaveM said:


> ...Longines VHP (poor TC of a crystal with a lot of thermal drift) !


Nonsense!


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## DaveM (Aug 9, 2008)

ppaulusz said:


> Nonsense!


I contribute to the forum & sometimes overstate in order to elicit responses which will increase my own & perhaps other peoples understanding.
So what in my post is nonesense ?
>HF crystal with better thermal drift than 32KHZ tuning-fork have been developed ?
>The accuracy of any compensation is only as good as the consistency and stability of the phenomena being compensated ?
>Thermal compensation of the new Longines VHP is poor ?
Discussions on this forum indicate that the new Longines VHP does not always meet 5spy when off the wrist.
It probably meets 10spy and the term 'poor' is severe, but in relation to the claimed 5spy the compensation mechanism does not appear to produce dependable results.


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## chris01 (Jan 5, 2011)

DaveM said:


> I contribute to the forum & sometimes overstate in order to elicit responses which will increase my own & perhaps other peoples understanding.
> So what in my post is nonesense ?
> >HF crystal with better thermal drift than 32KHZ tuning-fork have been developed ?
> >The accuracy of any compensation is only as good as the consistency and stability of the phenomena being compensated ?
> ...


IME, the new VHP (2 watches) is more temperature sensitive than any of my older VHPs (7 watches). This is not helped by the absence of any user-accessible regulation on the new watches. As for comparison with other TCs, my only experience is with the Certina DS-2 PreciDrive, which is worse than the old VHPs and better than the new, but is also not able to be regulated.


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## ppaulusz (Feb 11, 2006)

DaveM said:


> ...So what in my post is nonesense ?...


I can't make it clearer than I did the first time:
_Quote:_ ..._*Longines VHP (poor TC of a crystal with a lot of thermal drift) !*_
_My reply:_ _*Nonsense!*_


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## appleb (Sep 30, 2015)

gangrel said:


> And, the experience here has been that the 262 kHz movements don't generally perform to 10 SPY. Mind, they're really good within the overall quartz universe...30-60 SPY, IIRC, and that's fine for most of us...but Citizen, Seiko, and the Swatch brands can all point to accuracy of that level or better.


I have several Bulova UHF watches that run well within 10/spy.


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## DaveM (Aug 9, 2008)

ppaulusz said:


> I can't make it clearer than I did the first time:
> _Quote:_ ..._*Longines VHP (poor TC of a crystal with a lot of thermal drift) !*_
> _My reply:_ _*Nonsense!*_


I still do not understand why it is nonsense. 
Please can you provide some justification ?


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## gaijin (Oct 29, 2007)

I really don't understand why we tolerate so much "soft data" here in the HAQ forum.

Whether a particular watch deserves a place in this forum should not be a subjective decision.

If all that is offered to support inclusion, or exclusion, are soft data; e.g. feelings, opinions, hearsay, etc., then they should be rejected.

If hard data, e.g. accuracy tracking supported by accepted test protocol, support the general criterion for HAQ of +10spy performance, then the data will show whether it meets the criteria and should be included - otherwise, it should not.

So far, I see absolutely no hard data to support the OP's contention that his Bulova CURV Titanium should be included in this forum. Further, current manufacturer specs do not support +10spy performance.

If the OP were to publish some hard data which support a +10spy accuracy claim, then we can discuss it; but, until then, I see no grounds for including the OP's watch here.

To the OP:

Your watch is a very good looking piece. I like the idea of it, that it's Titanium, and that it is striving to be a cut above the average in performance. There is no reason you should not thoroughly enjoy it.

HTH


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## ronalddheld (May 5, 2005)

I prefer hard data, but others do not. 
Has there been any data collection on this watch,by long time members with the right equipment?


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## Tom-HK (Jan 6, 2015)

ronalddheld said:


> I prefer hard data, but others do not.
> Has there been any data collection on this watch,by long time members with the right equipment?


Not this model specifically, but a few of us have hard data on Precisionists, Accutron II and other related movements. I have gone through two Precisionists and an Accutron II, accepted protocols, and none has been near spec. That said, they were 'early' models and there has been some suggestion that not only have stated specs been loosened, but manufacturing quality may also have improved since the first iterations of these 262 kHz watches. I am not sure who has the latest hard data for any of the more up-to-date movements.


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## tmathes (Jan 11, 2013)

ronalddheld said:


> For modern watches,the standard is ~10s/y.


Then the Precidrive doesn't meet that standard. I have two examples of 50% and 100% above that standard.

And by that standard I have a couple of Bulovas are HAQ but two that are not, they're comparable to the Precidrives. Else the ETA movement drifts from the factory set point quickly or they don't trim within their own claims at the factory. One unit I can understand slips out the door but two in a row for one customer bought nearly a year apart? Um, no. I bought them from an AD so no excuses about abused/defective product that was dumped through gray channels.


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## ppaulusz (Feb 11, 2006)

DaveM said:


> I still do not understand why it is nonsense...


In that case just move on! Especially that it was not really you, who I targeted with my reply but the ones who visit this site/forum and are here to receive proper info about HAQ. So I really can't be bothered by your lack of understanding (whether it is a genuine one or a pretended one) as it is a matter of life that there will be always a certain percentage that make up the numbers but at the end of the day we all know that less could be more.


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## gaijin (Oct 29, 2007)

tmathes said:


> Then the Precidrive doesn't meet that standard. I have two examples of 50% and 100% above that standard.
> 
> And by that standard I have a couple of Bulovas are HAQ but two that are not, they're comparable to the Precidrives. Else the ETA movement drifts from the factory set point quickly or they don't trim within their own claims at the factory. One unit I can understand slips out the door but two in a row for one customer bought nearly a year apart? Um, no. I bought them from an AD so no excuses about abused/defective product that was dumped through gray channels.


Do you have any hard data you are willing to share that back all that up?

TIA


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## tmathes (Jan 11, 2013)

gaijin said:


> Do you have any hard data you are willing to share that back all that up?
> 
> TIA


Meaning measurements at monthly intervals over the past year? Month by month, no. I have four measurements, each at the daylight saving time change-over (US standard) over the last two years. I am comparing to time.gov, which also correlate to the time when I check my Citizen RC chronos in the morning (assuming I had a sync overnight). I'll have to dig up my data at home this weekend and post if that's adequate. Nice watches but HAQ using the 10 sec/ yr standard? Neither of my samples.

Since the DST changeover (I set the DS-2 on March 1, 10 days before DST changed since I don't wear either watch but every 2 weeks), my DS-2 chrono, which I'm wearing today, has gained 7 seconds. By my calculation that's trending to around 24 sec/yr. I don't observe the watch daily or weekly for how it's trending, I don't try to get sub-second measurements since I'm not going to start trying to take photos of sweep second hands in the act of moving. I record how fast/slow the watch is at the DST changeover on a post-it note under each watch in my watch box, that's close enough as far as I'm concerned since I'm measuring over months, and in the case of the DS-2, over a yearly period (I only fully adjusted it at the 1 yr. mark since I didn't care to get more than 30 sec. off).

I don't question the TC design but do question how accurately ETA trims these movements in production. Since neither watch was otherwise faulty I saw no reason to risk sending it to New Jersey to have them either return it the same as it was or screw-up something cosmetically.


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## BillSWPA (Feb 19, 2015)

gaijin said:


> I really don't understand why we tolerate so much "soft data" here in the HAQ forum.
> 
> Whether a particular watch deserves a place in this forum should not be a subjective decision.
> 
> ...


See my post above. I will add that I set and check all of my watches against the official US time website. Observing no more than 2 seconds off after a few months without being reset 3 different times throughout a year supports +/-10 sec./year.

Sent from my iPhone using Tapatalk


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## ronalddheld (May 5, 2005)

BillSWPA said:


> See my post above. I will add that I set and check all of my watches against the official US time website. Observing no more than 2 seconds off after a few months without being reset 3 different times throughout a year supports +/-10 sec./year.
> 
> Sent from my iPhone using Tapatalk


Really need to observe and measure throughout a year to take into account seasonal variations and different wearing patterns


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## tmathes (Jan 11, 2013)

What I recorded for my watches' accuracy.

I use time.gov to set each watch and double check with my Citizen RC chrono after a manual re-sync of that watch. To the best of my ability the Citizen RC seems to have the sweep second hand tick when time.gov ticks off a second. I've tried both using my phone on the ATT mobile network and with my home desktop PC hard-wired to my home's ISP. I couldn't detect any difference between my mobile phone and my home desktop so I use my mobile phone for convenience. Considering I made these measurements over a several months a 100ms or so error won't really matter:

Started tracking on 3/25/2016; set at 8:45pm.
4/24/2016, 7:55pm: +2 sec.
5/27/2016, 6:50pm: + 4 sec.
11/5/2016, 7:40pm : +16 sec.
03/8/2017, 7:25pm - +24 sec (cumulative from 3/25/2016)

reset watch on 3/8/2017 (used time.gov with double-checking with my Citizen RC chrono after a manual sync).

11/5/17, 7:50pm: +17 sec.
3/1/2018, +26 sec (cumulative since 3/10/2017)

reset watch on 3/1/2018. As of today, June 15, 2018 it's at + 7 seconds

Either I made a recording/measuring error in 2017 or 2018, some variation due to temps being different between the years or maybe different wear pattern over the year (or different times of the year). Like I said, I don't wear it but every 2 weeks but it's running around +24 sec/yr.

The DS-8

Started tracking on 12/2/2015; set at 3:35pm
1/2/2016, 9:05pm: +1.5 sec (made a note that the sweep second hand seemed to tick 1/2 second or so after time.gov ticked off a second and seemed to be the same when compared to my Citizen RC chrono).
2/3/2016, 7:20pm: +3 sec.
3/12/2016, 7:00pm: +4 sec (note that it was a fraction of a second above +4 sec but couldn't determine how much)
Reset watch on 3/12/2016 since the DS-8 doesn't have an IAHH.
11/5/2016, 7:50pm : +10 sec. (note that it was a fraction of a second above +10 sec) (reset watch)
03/10/2017, 7:45pm: +6 sec. (note that it was nearly a 6 sec., not fully but at least 2/3 to 3/4 of a second) (reset watch)
11/4/2017, 7:30pm: +11 sec (note that it was a fraction of a second below +11 sec) (reset watch)
3/10/2018, 7:50pm: +6 sec (no note that it was a fraction of a second above 6 sec). (reset watch).

The DS-2 seems to trend 16 to +17 sec./yr.

I haven't kept as close an eye on the Bulovas. I set the Bulovas on March 1, between 9:05pm and 9:35pm . What they read as of today:

- Lunar Pilot (aka Moon Watch): +3.5 sec (the 1/2 sec. ticking hand is helpful for this, took a snapshot but could be 4 sec?)
- Precisionist chrono: +4.25 sec. (took a snapshot since the smooth sweep second hand is tough to nail down with the eye, looked to be 1/4 between second marks)
- Curv: +5.5 sec (same as Lunar Pilot)
- Accutron II Surveyor: + 6.5 sec. (same as Precisionist chrono)

When I last set my Lunar Pilot, over the 8 month period from DST change-over it had gained 9 seconds (kept a note for this one). So far it appears to be the most accurate movement in my collection. Overall the four 262kHz Bulova/Citizen movements do well compared to my two ETA Precidrives.


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## BillSWPA (Feb 19, 2015)

ronalddheld said:


> Really need to observe and measure throughout a year to take into account seasonal variations and different wearing patterns


The watch was worn almost every day during the past year through all 4 seasons. It was checked at various times throughout that year.

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## wbird (Feb 25, 2015)

ronalddheld said:


> Really need to observe and measure throughout a year to take into account seasonal variations and different wearing patterns


Although nice to have those measurements not really necessary for most. You don't need to do all those measurements.

I live and work in a climate controlled environment like most people. When the watch is exposed to extreme weather conditions it's only for brief periods of time and it's on my wrist. When I looked for seasonal variation it was so small pretty much couldn't see it.

Data seems to show slight precision improvement if you wear a watch a lot, but again not a lot. Just need to identify how much the watch is worn with the data.

Historical data on this forum supports the premise that all those measurements are not necessary. They never seem to show a saw tooth pattern, unless it's running very close to 5 spy or less, and Bulova and Certina aren't usually in that region. Most watches seems to always trend either fast or slow, even the cheapest quartz watch.

If you like doing all those measurements and graphs that's great. But information and conclusions can be made from a few measurements a year.


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## gaijin (Oct 29, 2007)

tmathes said:


> What I recorded for my watches' accuracy.
> 
> I use time.gov to set each watch and double check with my Citizen RC chrono after a manual re-sync of that watch. To the best of my ability the Citizen RC seems to have the sweep second hand tick when time.gov ticks off a second. I've tried both using my phone on the ATT mobile network and with my home desktop PC hard-wired to my home's ISP. I couldn't detect any difference between my mobile phone and my home desktop so I use my mobile phone for convenience. Considering I made these measurements over a several months a 100ms or so error won't really matter:
> 
> ...


I'm having a hard time understanding which watch is associated with which data set - and what it all means in terms of SPY accuracy for each watch.

It should be possible for you to construct simple graphs for each watch showing the time offset over time and the corresponding SPY values.

If anyone (please understand I'm not addressing you personally with this) makes a statement about accuracy, they should be able and willing to provide a simple graphic summary of the data.

This thread is turning into a good (bad?) example of how statements about accuracy are made with a lot of "implied legitimacy" - i.e. the strong implication that there was careful data gathering to support the statement - when in fact there was not.

Anyway, it would be nice to see a graphical summary of your data to assure we all can understand it - or, at least, share a common understanding of what you are trying to show.

TIA


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## gaijin (Oct 29, 2007)

wbird said:


> If you like doing all those measurements and graphs that's great. But information and conclusions can be made from a few measurements a year.


That's fine, but we should see the data for those "few" measurements so we can draw our own conclusions. If there is nothing but a subjective report, then what do we really establish?

HTH


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## BillSWPA (Feb 19, 2015)

gaijin said:


> I'm having a hard time understanding which watch is associated with which data set - and what it all means in terms of SPY accuracy for each watch.
> 
> It should be possible for you to construct simple graphs for each watch showing the time offset over time and the corresponding SPY values.
> 
> ...


When I checked my accuracy, it was not in anticipation of participating in this thread. It was to satisfy myself that the watch was within spec.

Knowing that it was no more than 2 seconds off 3-4 months after the last time it was set, and repeated this performance, meets that objective.

Sent from my iPhone using Tapatalk


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## sertse (Sep 30, 2012)

ronalddheld said:


> For modern watches,the standard is ~10s/y.


Thanks for confirming. In my humble opinion, I feel the HAQ Forum should be a place where we can discuss watches with "higher than regular quartz accuracy" rather than just "only watches with less than 10 sec/year". At the heart of it, anyone who wanders here is because they are interested in accuracy, so they should be presented with all the options and tradeoffs (as long as it is supported by testing and hard data - which I what I like most about this forum) to make an informed decision.

There's room for two tiers of discussion as long as the facts are clear. I see that's how its enforced anyways so it's mainly whether it should be articulated that way too.

With Bulova the most uncontentious statement we can make is "Better than regular quartz accuracy with an official spec of 5 seconds/month, but may perform better anecdotally. Testing encouraged. There are other options if accuracy alone is the priority. Interesting design wise e.g. Curv, Sweeping Second. Price is generally cheaper especially on the grey market. So consider whether that combination of tradeoffs + your own opinions of looks to see if suits you".

----

As for people with hard(ish) data; wbird has logged his ongoing observations through since early 2016 (for 2015-2016) in the "Bulova meets specs" thread...which is either 10sec year or +1/2 seconds which was why he named the thread that way.

tmathes data above indicates in between: (I'm using DD/MM/YYY)

1) 24/4/2016 to 8/3/2017 (319 days) there was +24 seconds: 27.5 seconds per year.
2) 10/3/2017 to 1/3/2018 (357 days) there was +26 seconds: 26.6 seconds per year.
3) 1/3/2018 to 15/6/2018 (107 days) there was +7 seconds: 23.9 seconds per year.

Tom-HK has a whole site to his testing and methodology and based on what he had there: Data it's around -15 or + 20 seconds per year on his two watches.

I only owned my (old production) Bulova for a month, but I have been tabling my test and from 32 days it is 2.21 seconds off: 25.2 seconds per year.

Sorry if I missed anyone else who made ongoing timings; these are just the names I see most often.

It was based on this data that I made my earlier post that the OP could probably expect around 25 spy, even though official spec is 60 spy and encouraged him to test to add more data to the post.


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## ronalddheld (May 5, 2005)

sertse said:


> Thanks for confirming. In my humble opinion, I feel the HAQ Forum should be a place where we can discuss watches with "higher than regular quartz accuracy" rather than just "only watches with less than 10 sec/year". At the heart of it, anyone who wanders here is because they are interested in accuracy, so they should be presented with all the options and tradeoffs (as long as it is supported by testing and hard data - which I what I like most about this forum) to make an informed decision.
> 
> There's room for two tiers of discussion as long as the facts are clear. I see that's how its enforced anyways so it's mainly whether it should be articulated that way too.
> 
> ...


This is not a general Quartz forum, only for HAQ, some RC/GPS watch discussions and few vintage HAQ watches. Mr. Moderator endeavors to keep the forum more tightly focus than others.


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## ronalddheld (May 5, 2005)

sertse said:


> Thanks for confirming. In my humble opinion, I feel the HAQ Forum should be a place where we can discuss watches with "higher than regular quartz accuracy" rather than just "only watches with less than 10 sec/year". At the heart of it, anyone who wanders here is because they are interested in accuracy, so they should be presented with all the options and tradeoffs (as long as it is supported by testing and hard data - which I what I like most about this forum) to make an informed decision.
> 
> There's room for two tiers of discussion as long as the facts are clear. I see that's how its enforced anyways so it's mainly whether it should be articulated that way too.
> 
> ...


This is not a general Quartz forum, only for HAQ, some RC/GPS watch discussions and few vintage HAQ watches. Mr. Moderator endeavors to keep the forum more tightly focus than others.


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## tmathes (Jan 11, 2013)

gaijin said:


> I'm having a hard time understanding which watch is associated with which data set - and what it all means in terms of SPY accuracy for each watch.
> 
> It should be possible for you to construct simple graphs for each watch showing the time offset over time and the corresponding SPY values.
> 
> ...


I don't have granular data to generate graphs, I do not track it daily/monthly, I'm not that preoccupied with how accurate my watches are to use that kind of time. I record the errors at the DST change over so there's nothing to plot that will show variations with temperature over time.

So many of you on this board say to see what variation you have must be recorded over a year for a true picture of how accurate the watch is so my observations and recorded data for the Certinas are exactly that, over a two year period to get an idea of the accuracy of the ETA Precidrives. The Bulovas I only have what the drift/error was since March 1, 2018.

Synopsis:

*Certinas (observed over a 2 yr. period):

DS-2 chronograph, Ti version: +24 sec/yr (observed over a 2 year period)
DS-8: +16 sec/yr.*

*Bulovas (observed over a 3.5 month period, I normalized it for a year):

Lunar Pilot: +12 sec/yr
Precisionist chronograph: +15 sec/yr.
Curv: +19 sec. yr.
Accutron II Surveyor: +22 sec/yr.
*

Is that clearer now? Discount the Bulova observations if you wish but from the two samples of the ETA Precidrives I own they ain't "HAQ" if 10 sec/yr. is the standard. If ETA can't produce their claimed accuracy repeatedly in unit after unit then it isn't HAQ. I have two samples that show that. I wore them both daily the first few months I owned both watches, I saw no real difference in accuracy on or off the wrist so the TC does seem to work. They just cannot be claimed to be HAQ just because they have temperature compensation if they're not accurate to within 10 sec/yr. consistently out of the box sample after sample. I have two samples, bought months apart that show that.

ETA doesn't have a good trim method to match those claimed "specs" watch-after-watch, just like Bulova couldn't with the Precisionist when they claimed the same and were blasted in this forum for one or two units that weren't spot on. At least Bulova was honest, they implicitly admitted as such when they changed to 5 sec/month.

In my experience the Citizen 262kHz movement is just as accurate as the ETA Precidrive and I have six samples that I base that claim with. You want to ignore it? That's OK with me, it's not worth arguing over.


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## gaijin (Oct 29, 2007)

tmathes said:


> That's OK with me, it's not worth arguing over.


I agree. Thanks for posting.


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## wbird (Feb 25, 2015)

Clearly the mention of Bulova on this forum tends to create a contentious thread. It doesn't appear that all the recent data can move some opinions here. That's okay that's why we measure things and post the results.

This forum was created to discuss cutting edge technology associated with high accuracy quartz watches. Based on that criteria doesn't Bulova qualify?

Sure there are watches that have higher frequency, but Bulova is still operating at a frequency higher than 99% of the watches on the market.

It has a precision that is better than say 99% of the quartz watches on the market, including that Curv.

We talk a lot about TC, a lot less about thermal insensitivity and that higher frequency watches may exhibit this trait and not require a great deal of TC to perform as well as say a Certina.

On top of all that there isn't a chronograph on the market that combines a sweeping and ticking second hand.

I think it is easier to make the case for Bulova here than Precidrive and yet never see any emotion with that brand.

Enough on that. I want to address graphs and amount of measurements required. When I started tracking both the Bulova and Certina I tracked them monthly, and found that drift versus time was linear with correlation coefficient of close to 1. Based on that I wasn't getting any additional information by taking more measurements. So I applied the basic mil spec approach to sampling and testing, a couple of measurements a year at DST normalized to spy are more than adequate. Not much point is graphing a couple of points.


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## PetWatch (Nov 24, 2016)

I have not seen any mention regarding battery condition. I have a Bulova Precisionist 96B228 that was getting 9 spy over a 10 month period with unknown battery condition at first measurement. (Measured six times using online atomic clock, about two months on wrist, rest off.) Last measurement taken 15 months after initial one results in 14 spy. According to the Bulova manual they recommend "a fresh power cell designed to provide maximum reliability for approximately a year under normal use". So I would think that condition of power cell is critical to determine optimum performance.


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## BillSWPA (Feb 19, 2015)

I find it very disappointing that in 2018 we have so few watch companies making and advertising high accuracy quartz, and am glad Bulova did so. My Sea King has almost spoiled me with respect to accuracy, and I am starting to balk at watch makers who set a price of multiple thousands of dollars while providing little information about either their selection of movement or the accuracy the purchaser can expect. If the list price is above $1,000, I would really like to see more information about the movement beyond simply "quartz." I suggest that those companies are more deserving of criticism than a company like Bulova that made a good effort, may or may not have failed at one point, but appears to be succeeding now.

I previously put the Watch Tracker app on my phone primarily to keep track of a different mechanical watch, but partly as a result of this and the other Bulova thread, I began tracking my Sea King yesterday. I put in a new battery a couple of weeks ago, so it is beginning with a basically new battery. Hopefully in a month or so I can switch from supplying "hard-ish" date to "hard" data.

I will track a few other quartz watches as well. In particular, my Luminox, which was purchased in 2002, has generally kept to about 4-5 sec/month using very loose tracking methods. It will be interesting to see whether that changes using a more precise tracking method.


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## tmathes (Jan 11, 2013)

PetWatch said:


> I have not seen any mention regarding battery condition. I have a Bulova Precisionist 96B228 that was getting 9 spy over a 10 month period with unknown battery condition at first measurement. (Measured six times using online atomic clock, about two months on wrist, rest off.) Last measurement taken 15 months after initial one results in 14 spy. According to the Bulova manual they recommend "a fresh power cell designed to provide maximum reliability for approximately a year under normal use". So I would think that condition of power cell is critical to determine optimum performance.


Not necessarily.

The basic circuits in a watch (oscillators, precision voltage references, logic circuits in particular) can be designed to operate over a rather wide voltage range, meaning 0.9-1.6V (for a silver oxide 1.5V cell) or 1.2V-3V (for a litium button cell) and keep their accuracy. It's standard design practice.

I design precision analog integrated circuit (IC) blocks as part of my job and those basic circuits I mentioned are in nearly every mixed signal (meaning analog and digital on one) IC, we always design them for a wide voltage supply range. There are several standard circuit designs that will make a circuit rather insensitive to voltage headroom, the circuit keeps working then will rapid 'fall off a cliff' over a narrow supply range. They basically work within spec then go kaput when the power rail drops below a certain voltage.

Bulova is covering their backsides with the statement you quoted from the manual, it minimizes customer returns or complaints. Any remotely decent quartz watch will keep proper time until the battery gets too low. At that point the movement just stops and you'll need a new battery at that point; it's not necessary to replace it until then. If you want to be safe and not get caught with a stopped watch when you least can afford it, if your watch has an End Of Life feature (like the sweep second hand jumped several seconds at a time, meaning "replace da battery fool"), do it then. Otherwise, a low battery won't affect time keeping.

Most owners of these Bulova watches have been reporting battery life way longer than Bulova claims (1-2 yrs.), it's been more like 3-4 yrs. My oldest ones are 2 yrs. old, no battery change needed and they're still well within 5 sec/month. If you have a chrono the best way to improve battery life to WAY longer than the manual says is to not use the chrono much.


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## gangrel (Jun 25, 2015)

tmathes said:


> If you have a chrono the best way to improve battery life to WAY longer than the manual says is to not use the chrono much.


Which, of course, potentially begs the question of why you paid for the chronograph in the first place. 

Altho I don't think a quartz chronograph carries as large a premium, nor do you have to worry about the ongoing premium on servicing.


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## BillSWPA (Feb 19, 2015)

I took my first WatchTracker data point on the Sea King about 5 days ago. The time was last reset at the beginning of June after a pre-travel battery change, and the first data point is -0.1 seconds deviation from official US time. The data point from today showed 0.0 change over the previous 5 days, still -0.1 seconds different from official US time.

While I cannot say that the watch started out at 0.0 seconds deviation from official US time, it was originally set as close as I could possibly get it to official US time.

My hard data is still over a very limited time period but confirms my “hard-ish” data.



Sent from my iPhone using Tapatalk


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## Hans Moleman (Sep 24, 2007)

The high frequency 8F56 movements from Seiko had a problem with aging.
They would perform well the first year, but later years would see a dramatic decline.

The same was noticed with the Bulova high frequency movements.

If that has been remedied with the more recent models I don't know.
"Next release will fix all that".

Has it?


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## ppaulusz (Feb 11, 2006)

Earlier I was not really interested in the 262kHz Bulova because:
- the similar Seiko 8F movements with their 196kHz quartz were not top performers accuracy-wise in my (and many others) experiences
- Bulova did not use sapphire glass until recently with the 262kHz movements

Now I changed my mind and purchased a brand new _Bulova Curv 98A160 chronograph_ because:
- it is fitted with sapphire glass
- I like its design and aesthetic (I won't use its minimalist chronograph function and I'm not bothered by the lack of the calendar)
- accuracy-wise it will be a matter of luck (factory calibration is always a matter of luck)
- it is a good candidate for a _scientific purchase_ (to find out its performance precision/accuracy-wise);-)

Since this model is not available in Hungary, I purchased it from a UK authorized seller with 3 years Bulova warranty.
The watch will be delivered sometime next week.
I will immediately test its precision with my quartz tester/analyzer to establish its run. Of course this won't be an indication for its performance at a different temperature-range still the info will be useful as it will show whether it is within say COSC/quartz chronometer specification (in the given temperature).
This is the picture of the above mentioned model:


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## Hans Moleman (Sep 24, 2007)

ppaulusz said:


> - it is a good candidate for a _scientific purchase_ (to find out its performance precision/accuracy-wise);-)
> 
> :


Always in for a challenge! Good on ye!

I've been thinking how to read a 6 twitches per second movement.
Haven't got a solution yet.


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## ronalddheld (May 5, 2005)

ppaulusz said:


> Earlier I was not really interested in the 262kHz Bulova because:
> - the similar Seiko 8F movements with their 196kHz quartz were not top performers accuracy-wise in my (and many others) experiences
> - Bulova did not use sapphire glass until recently with the 262kHz movements
> 
> ...


Awaiting years of test results.


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## gaijin (Oct 29, 2007)

Hans Moleman said:


> Always in for a challenge! Good on ye!
> 
> I've been thinking how to read a 6 twitches per second movement.
> Haven't got a solution yet.


The Bulova 262 kHz chronos with the small second hand only "twitch" twice per second.

HTH


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## gaijin (Oct 29, 2007)

Hans Moleman said:


> Always in for a challenge! Good on ye!
> 
> I've been thinking how to read a 6 twitches per second movement.
> Haven't got a solution yet.


Don't know if you are referring to the Bulova 262 kHz second hand when you mention 6 twitches per second, but the models with the large center seconds hand twitch at a much higher rate than that. Based on this one second exposure, the second hand appears to twitch somewhere around 18-20 times per second[Edit: Bulova spec is 16 times per second]:










I'm sure a precise frequency for the large second hand has been published somewhere, but I can't seem to find it offhand.

HTH

Ha! Found it in my own post: https://www.watchuseek.com/f21/bulova-precisionist-how-smooth-seconds-hand-657447.html

Looks like the Bulova spec is 16 ticks per second.


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## Hans Moleman (Sep 24, 2007)

gaijin said:


> Don't know if you are referring to the Bulova 262 kHz second hand when you mention 6 twitches per second, but the models with the large center seconds hand twitch at a much higher rate than that. Based on this one second exposure, the second hand appears to twitch somewhere around 18-20 times per second[Edit: Bulova spec is 16 times per second]:
> 
> 
> 
> ...


Great picture.

The standard way is to keep one selves deaf for the period one is not interested in. The 15 ticks out of the 16. And only start listening when the 16 is about to come up.

That next day you can't remember which one is which.


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## ppaulusz (Feb 11, 2006)

Hans Moleman said:


> Always in for a challenge! Good on ye!
> 
> I've been thinking how to read a 6 twitches per second movement.
> Haven't got a solution yet.


My quartz tester/analyzer will have no problem to correctly read the 2 ticks/second of the small second-hand of this particular CURV model as it could read correctly even the 3 ticks/second of the Morgenwerk M1... but it would certainly fail to read correctly the 16 ticks/second of the Precisionist though I've never tested that one.


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## Hans Moleman (Sep 24, 2007)

ppaulusz said:


> My quartz tester/analyzer will have no problem to correctly read the 2 ticks/second of the small second-hand of this particular CURV model as it could read correctly even the 3 ticks/second of the Morgenwerk M1... but it would certainly fail to read correctly the 16 ticks/second of the Precisionist though I've never tested that one.


No sweeping hand on this one. Missed that.
You've thought about it!
|>


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## ppaulusz (Feb 11, 2006)

ronalddheld said:


> Awaiting years of test results.


I do not have great expectation about the 262kHz technology... if it would perform within 2 seconds/month then I would not complain... if it would be within 1 second/month then I'd be very happy... I can't even dream a better than 5 seconds/year performance from that technology.
There must be a reason (a good one) that Citizen opted for 8.4MHz + thermocompensation in the case of the new super precise/accurate Cal.0100. 262kHz is simply not far enough from the standard 32kHz. I'm not aware of any thermocompensation scheme involved with the Bulova 262kHz movement only the relatively high frequency (that is 8-times higher than the standard 32kHz but very far from the 4.19MHz or 8.4MHz steroid-driven calibers).


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## ppaulusz (Feb 11, 2006)

Hans Moleman said:


> No sweeping hand on this one. Missed that.
> You've thought about it!
> |>


Sure, I did... in the name of science!


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## ronalddheld (May 5, 2005)

A 262 Khz watch is cheaper to produce then the Caliber 0100 wristwatches will be.


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## ppaulusz (Feb 11, 2006)

ronalddheld said:


> A 262 Khz watch is cheaper to produce then the Caliber 0100 wristwatches will be.


That is for sure!

However my point is that 262kHz combined with current thermocompensation scheme (perhaps with a little fine-tuning) should easily deliver(!) within 4 seconds/year with better percentage than the current within 5 seconds/year or within 10 seconds/year calibers when we compare the promises with the actual performances.
Well, Citizen owns both technologies: 262kHz and thermocompensation still Citizen is not interested to create an affordable top performer by combining these technologies. Rather it went to create a most probably very expensive super precise movement (Cal.0100) that might be out of financial reach for most of us.


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## gangrel (Jun 25, 2015)

ppaulusz said:


> There must be a reason (a good one) that Citizen opted for 8.4MHz + thermocompensation in the case of the new super precise/accurate Cal.0100.


They're using what looks to be a rather more expensive crystal cut...larger, harder to get right. This is in the usual range for the cut they're using. We covered a lot of this in the Cal 0100 thread back in March.

If you're asking, why not just do 262 kHz with TC? Maybe they don't want to associate the 0100 with the Precisionists. Perhaps they think consumer response to the 262 kHz has been lackluster. Alternately, they're opting for a lab-grade crystal cut, which can be promoted better. Or, it wouldn't surprise me the AT cut exhibits less thermal sensitivity in the range that matters for a watch.

Or it could be pure PR.

We're not ever gonna know.


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## PetWatch (Nov 24, 2016)

This snippet is taken from a watch review article from Timezone.com, it mentions improved temperature variance due to the "three-prong torsional quartz crystal resonator that twists instead of oscillates back-and-forth". It mentions the old claim of 10spy, nevertheless most accuracy accounts that I have seen in WUS are close to or better than 10spy. Along with, or without?, the UHF quartz, this non regulated form of temperature compensation appears to be good enough to produce a remarkably accurate watch, especially at it's price point. Looking forward to your comments.

TimeZone : Watch Reviews Â» Bulova Accutron II Alpha UHF & Accutron II Lobster UHF (with video)

*UHF Movement with Torsional Quartz Crystal Resonator*
The caliber BA101.10 is a high-grade, 8-jewel, 10 ligne 262.144 kHz UHF quartz movement that achieves a remarkable accuracy of ±10 seconds per year (or ±0.027 second per day), which is eight times greater than a standard quartz movement. Since a UHF movement is silent, I could not independently measure its accuracy on my timing machine.

However, at the heart of Bulova's UHF movement is sound research invented by Dr. Hirofumi Kawashima, who's been engaged in the research and development of quartz crystal resonators for watches, coupled quartz crystal resonators, peripheral flexural resonators, extensional resonators, various piezoelectric sensors (temperature, vacuum, weight, and acceleration), high precision quartz crystal oscillators (S-TCXO) and piezoelectric actuators since the 1970s. In 1994, Dr. Kawashima invented the torsional quartz crystal resonator and assigned his patented invention to Seiko Electronic Components Ltd.








Patent illustration of Dr. Hirofumi Kawashima's torsional quartz crystal resonator invention

Similarly, Bulova's UHF technology is based on a three-prong torsional quartz crystal resonator that twists instead of oscillates back-and-forth. The torsional quartz crystal resonator's innovative construction reduces the effects of temperature variation without a thermo-regulating integrated circuit. Specifically, frequency temperature behavior is improved by its unique cut angle, an optimal thickness-to-width ratio, unique shape and excitation electrode structure. In laboratory testing between −30°C to +70°C, the torsional quartz crystal resonator exhibited good frequency temperature behavior under a range of temperatures.

In addition, the movement's innovative three-prong torsional quartz oscillator design reduces the effects of temperature variation without the high maintenance of a thermo-compensated IC.


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## Tom-HK (Jan 6, 2015)

I don't believe Seiko ever used this particular technology, but in the 1980s they did develop and deploy a twin mode oscillator that combined both flexural and torsional resonance modes in a 196 kHz package. There was a tri-pronged oscillator patented at about the same time, but not by Seiko. Both those patents expired about a year or two before Bulova came to market with their tri-pronged, torsional oscillator in their Precisionist line. The 1994 patent is not likely to be directly relevant to the 262 kHz movement's development as the patent on that would have expired only a couple of years ago.


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## wbird (Feb 25, 2015)

Not sure if Citizen is sitting on patents that reference Kawashima's work and expanded on it, and employed it in that Bulova. But I think the point PetWatch was making is that the tri-prong torsional oscillator movement appears to be more temperature insensitive. May explain why my and others have Bulova's that have little or no TC, that routinely show higher precision than quite a few Certina's with TC.


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## ppaulusz (Feb 11, 2006)

ppaulusz said:


> I do not have great expectation about the 262kHz technology... if it would perform within 2 seconds/month then I would not complain... if it would be within 1 second/month then I'd be very happy... I can't even dream a better than 5 seconds/year performance from that technology...


My *Bulova Curv 98A160* chronograph finally has arrived and I've just checked its off-wrist accuracy/precision (at room temperature of 28 degree of Celsius after fresh battery installation and 12 hours resting at room temperature for proper settling down) with my professional (GPS-calibrated) quartz tester/analyzer. It is currently running at +0,04 second/day or about +15 seconds/year. I'm happy with that performance and would be even happier if it would improve when worn (on-wrist).
The watch is the 2016 edition (B6) release (the first one) so if there is any quartz ageing involved with this movement (perhaps it is not an issue at all) then this one is about 2 years old already (the watch is brand new but from the very first stock from 2016). 
Please note that as the room temperature increased to 30 degree of Celsius the running of the watch speeded up to +0,05 second/day or about 18 seconds/year (I measured the watch for 60 minutes and during that period the room temperature went from 28 to 30 degree of Celsius.). To be continued...;-)


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## ppaulusz (Feb 11, 2006)

ppaulusz said:


> My Bulova Curv 98A160 chronograph finally has arrived and I've just checked its off-wrist accuracy/precision (at room temperature of 28 degree of Celsius after fresh battery installation and 12 hours resting at room temperature for proper settling down) with my professional (GPS-calibrated) quartz tester/analyzer. It is currently running at +0,04 second/day or about +15 seconds/year. I'm happy with that performance and would be even happier if it would improve when worn (on-wrist).
> The watch is the 2016 edition (B6) release (the first one) so if there is any quartz ageing involved with this movement (perhaps it is not an issue at all) then this one is about 2 years old already (the watch is brand new but from the very first stock from 2016).
> Please note that as the room temperature increased to 30 degree of Celsius the running of the watch speeded up to +0,05 second/day or about 18 seconds/year (I measured the watch for 60 minutes and during that period the room temperature went from 28 to 30 degree of Celsius.). To be continued...;-)


I managed to carry out the on-wrist measurement (I had to use a rubber-band to fix the sensor to the watch on my wrist) and here is the result: the watch runs at +0,06 second/day or about at +22 seconds/year (on-wrist at room temperature of 28 degree of Celsius measured for 60 minutes and the watch had been worn for 10 hours before I started the measurement at this environment).
I'm aware that both of these measurements are somewhat artificial as the test environment (the room in this case) is non-variable. Unfortunately, the quartz tester/analyzer measurements cannot be carried out in a constantly variable environment. Still these tests are very useful for two reasons. First of all they are relatively quick (takes an hour or so each with preparation). The other useful thing is that these test results indicate a trend (the warmer the environment, the faster the watch runs - at least within these temperature ranges). Now it's summer time at my location (continental climate with 4 distinctive seasons) so it will be colder here in the rest of the year (autumn, winter, spring) and that will slow down the run of the watch (in theory based upon my test results) and that should result an excellent _all-over-the-year_ performance (accuracy-wise) in my opinion.


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## PetWatch (Nov 24, 2016)

ppaulusz said:


> Now, the bracelet is resized and the 2 years old original battery is replaced with a fresh one.
> I managed to carry out the on-wrist measurement (I had to use a rubber-band to fix the sensor to the watch on my wrist) and here is the result: the watch runs at +0,08 second/day or about at +29 seconds/year (on-wrist at room temperature of 28 degree of Celsius).
> I'm aware that both of these measurements are somewhat artificial as the test environment (the room in this case) is non-variable. Unfortunately, the quartz tester/analyzer measurements cannot be carried out in a constantly variable environment. Still these tests are very useful for two reasons. First of all they are relatively quick (takes an hour or so each with preparation). The other useful thing is that these test results indicate a trend (the warmer the environment, the faster the watch runs - at least within these temperature ranges). Now it's summer time at my location (continental climate with 4 distinctive seasons) so it will be colder here in the rest of the year (autumn, winter, spring) and that will slow down the run of the watch (in theory based upon my test results) and that should result an excellent _all-over-the-year_ performance (accuracy-wise) in my opinion.


Good to see your high precision tests in addition to the other less precise methods and anecdotal samples.

Interesting, where I live outdoor temperatures typically fluctuate 20C/30F and greater throughout the year, even taking into consideration that the watch will be worn when outdoors it seems to me it could easily experience significantly greater temp. changes than the one in your tests, especially when going from a cooled indoor environment to a very hot outdoor one or vice-versa.

If it's not too much trouble it would be interesting to see the off the wrist temp. test with the new battery, just to confirm that the difference between a new (off the shelf), and a used 2 year old battery has no impact on accuracy. I realize there shouldn't be a difference within the battery's useful life.


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## ppaulusz (Feb 11, 2006)

PetWatch said:


> Good to see your high precision tests in addition to the other less precise methods and anecdotal samples.
> 
> Interesting, where I live outdoor temperatures typically fluctuate 20C/30F and greater throughout the year, even taking into consideration that the watch will be worn when outdoors it seems to me it could easily experience significantly greater temp. changes than the one in your tests, especially when going from a cooled indoor environment to a very hot outdoor one or vice-versa.
> 
> If it's not too much trouble it would be interesting to see the off the wrist temp. test with the new battery, just to confirm that the difference between a new (off the shelf), and a used 2 year old battery has no impact on accuracy. I realize there shouldn't be a difference within the battery's useful life.


Thanks for the feedback and for the advice about re-testing the off-wrist performance with the new battery!|>
Now I did re-test it (off-wrist, room temperature of 28 degree of Celsius) and the result indicates an improved precision/accuracy (+0,04 second/day or around +15 seconds/year) but most probably not because of the battery replacement but because this time the watch was subjected to this environment for 12 hours (instead of 1 hour earlier). Usually 1 hour at room temperature is enough when the watch is thermocompensated to subject it to test measurements however this watch is not thermocompensated but has a higher frequency quartz and it needs more time at the given temperature to show proper results. Last time I gave it 1 hour only to settle down after the courier delivery. I think that was just not enough. 
Please note that as soon as the room temperature increased to 30 degree of Celsius, the running of the watch speeded up to +0,05 second/day or about +18 seconds/year just as I was finishing this posting (I measured the watch for 60 minutes and during that period the room temperature went from 28 to 30 degree of Celsius.). 
Now, I corrected/updated my earlier posting to show the proper results and circumstances. 
I will wear it for 8-12 hours at room temperature and will re-test the on-wrist performance at room temperature so I'll get back with that update as well later on.


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## ppaulusz (Feb 11, 2006)

ppaulusz said:


> ...I will wear it for 8-12 hours at room temperature and will re-test the on-wrist performance at room temperature so I'll get back with that update as well later on.


I've concluded the on-wrist re-test at room temperature of 28 degree of Celsius (measured for 60 minutes and the watch had been worn for 10 hours before I started the measurement at this environment) and here is the result: the watch runs at +0,06 second/day or about at +22 seconds/year.
Now, I corrected/updated my earlier posting to show the proper results and circumstances.


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## dicioccio (Jul 14, 2011)

According to this and the data from other users (reported here and there on WUS) we can say that the HF Bulova calibers are more or less accurate as the TC Certina precidrives. This could be intended as a good result for the HF Bulova as well as a poor result for the TC precidrive. Anyway I would be courious to know the opinion of Mr. Moderator about the right label we should give to these calibers: they are certainly better than standard quartzes but they don't meet the accuracy of 10 spy required to properly call them HAQ. So what should we do ?


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## gangrel (Jun 25, 2015)

dicioccio said:


> Anyway I would be courious to know the opinion of Mr. Moderator about the right label we should give to these calibers: they are certainly better than standard quartzes but they don't meet the accuracy of 10 spy required to properly call them HAQ. So what should we do ?


Sit back, relax, and have a homebrew.


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## ronalddheld (May 5, 2005)

gangrel said:


> Sit back, relax, and have a homebrew.


Good idea,while I ruminate over this.


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## dicioccio (Jul 14, 2011)

ronalddheld said:


> Good idea,while I ruminate over this.


Yesssssss, I did it - great suggestion !!!


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## gangrel (Jun 25, 2015)

dicioccio said:


> <deleted - double post - too much beer ! >


Touchy forum software. Never blame the beer.

(Besides, I've had that happen a BUNCH in the last few weeks, even when stone cold sober and properly caffeinated.)

Ohhh...I just realized, I've got chili on the menu for the 4th. Gives me an excuse to break out a specialty bottle, drink half tonight, save half for the chili.

Scuse me, time to check what's left in the beer fridge.....


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## Hans Moleman (Sep 24, 2007)

ppaulusz said:


> I've concluded the on-wrist re-test at room temperature of 28 degree of Celsius (measured for 60 minutes and the watch had been worn for 10 hours before I started the measurement at this environment) and here is the result: the watch runs at +0,06 second/day or about at +22 seconds/year.
> Now, I corrected/updated my earlier posting to show the proper results and circumstances.


Thanks ppaulusz!

Summer in Hungary. Who would have thought you guys could get up to 30 degrees Celsius?
I imagine Hungary as a landscape with churches covered in snow.

And it looks like room temperatures of 20 degrees Celsius slow it down to better off-wrist rates.
Another test in autumn perhaps?


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## ppaulusz (Feb 11, 2006)

Hans Moleman said:


> Thanks ppaulusz!
> 
> Summer in Hungary. Who would have thought you guys could get up to 30 degrees Celsius?
> I imagine Hungary as a landscape with churches covered in snow.
> ...


Hans, "landscape with churches covered in snow" can happen in winter in this part of the world.

Yes, according to my test results, lower room temperature (within a certain range!) would result a slower running of the watch that in my case would be a more accurate watch. Strange enough that I read in our HAQ forum here (post #54):
https://www.watchuseek.com/f9/bulova-meets-specs-2997882-6.html
that "..._I have this Bulova Sea King, it runs perfectly IF I wear the watch BUT leaving alone ( means: at lower temperature ) it runs faster_..."
Now, that Bulova Sea King uses a different movement than my Bulova CURV but both movements are based on the same 262kHz high-frequency quartz... so here we go... a bit of a mystery.
Actually, I would welcome any owner's feedback that would indicate that his/her Bulova 262kHz watch runs faster or slower at lower temperature. I do not even need the exact figures just the trend/direction: slower or faster at lower temperature? (or slower or faster at higher temperature?).

Sure, I will conduct more tests as seasonal changes will take place.;-)


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## ppaulusz (Feb 11, 2006)

ppaulusz said:


> ...I will conduct more tests as seasonal changes will take place.;-)


Actually, I can do a pretty good winter weather test right now!:-!

30 minutes ago I took the watch off my wrist, put it into a small plastic bag and put this little package into my refrigerator that is digitally set at a temperature of +4 degree of Celsius. I attached the sensor of my quartz tester/analyzer to the package and it reads perfectly the "ticks" as the main unit of the tester/analyzer is kept on room temperature. 
Now, that +4 degree of Celsius (off-wrist, of course) should equal to a very cold sub-zero degree of Celsius temperature when the watch is on-wrist... like a very cold winter day outdoor with the watch on the wrist. 
I started the measurements after the 30 minutes "cooling off" period and I set a target duration of 60 minutes... to be continued!;-)


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## ppaulusz (Feb 11, 2006)

ppaulusz said:


> ...+4 degree of Celsius (off-wrist, of course) should equal to a very cold sub-zero degree of Celsius temperature when the watch is on-wrist... like a very cold winter day outdoor with the watch on the wrist.
> I started the measurements after the 30 minutes "cooling off" period and I set a target duration of 60 minutes... to be continued!;-)


Here are the results:
- after 10 minutes of measurement (that means the watch had already spent 40 minutes in the refrigerator) it run at an average +0,01 second/day or about + 4 seconds/year
- after 30 minutes of measurement (that means the watch had already spent 60 minutes in the refrigerator) it run at an average 0,00 second/day
- after 45 minutes of measurement (that means the watch had already spent 75 minutes in the refrigerator) it run at an average 0,00 second/day
- after 59 minutes of measurement (that means the watch had already spent 89 minutes in the refrigerator) it run at an average 0,00 second/day

The pictures show the second/day (in black) averaged for the measured period in minutes (pink).

Conclusion: at extreme cold (on-wrist) temperature the watch was extremely accurate (dead on!!!) and at a warm temperature (on-wrist) it run at +0,06 second/day or about 22 seconds/year (as per my earlier post). I think that my tests show that Bulova indeed made an excellent temperature insensitive movement that might perform (according to my test and some speculation from my part) all year around at an average of +1 second/month... at least that particular watch that I had the pleasure of testing. Naturally, I'd be very happy with _that_ performance and I'm sure that it can't be far from that "_projected_" performance.

Finally, here are the pictures:


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## ppaulusz (Feb 11, 2006)

ppaulusz said:


> ...my tests show that Bulova indeed made an excellent temperature insensitive movement that might perform (according to my test and some speculation from my part) all year around at an average of +1 second/month...


Be *WARNED* that the following thoughts are just speculations that means that I might have something here or I might be completely wrong...:-s

I do have a problem with my Bulova 262kHz watch: it is too accurate/precise for a purely 262kHz watch!:roll:

Years ago I had a Seiko Perpetual Calendar watch with the 8F movement that used a 196kHz high-frequency quartz with a claimed accuracy of within 20 seconds/year. The performance of that watch was nowhere near the claimed accuracy and many users reported similar out of specifications performances from their Seiko 8F fitted watches. Seiko soon ceased the manufacturing of these 196kHz watches... Then in 2010 Bulova (owned by that time by Citizen) introduced its 262kHz fitted high-frequency watches with a claimed accuracy of within 10 seconds/year. Again, most of the owners complained that these watches did not meet factory specifications (actually they missed those specifications by a fairly large margin). As a response to those complain Bulova changed the specifications (regarding to accuracy) and left out the "_within 10 second/per year_" criteria and instead unofficially they used the "_within 5 seconds/month_" claim. A couple of years passed and since around 2014 owners started reporting much better accuracy-performances regarding their new Bulova 262kHz watches. This increased accuracy partly might be explained by tighter factory calibration or by better selection or preparation of the 262kHz quartz crystals or... by a silent introduction of some sort of thermocompensation circuitry. If your parent company is Citizen then you might just well ask for some parental help/assistance. I don't intend to suggest that Citizen offered Bulova their top of the line thermocompensation scheme but even with a small aid by thermocompensation the 262kHz movement can perform a great deal better than without it. With full blown thermocompensation the 262kHz movement's accuracy would be better than within 4 seconds/year, in my opinion. With lightly applied thermocompensation (_thermocompensation-light _scheme) the 262kHz movement would achieve results like I got with my watch. Without any thermocompensation I seriously doubt that my watch would show such a great "_thermo-insensivity_".

As I mentioned in the first sentence: be *WARNED* as the above conclusion is pure speculation from my behalf!:think:


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## ronalddheld (May 5, 2005)

ppaulusz said:


> Be *WARNED* that the following thoughts are just speculations that means that I might have something here or I might be completely wrong...:-s
> 
> I do have a problem with my Bulova 262kHz watch: it is too accurate/precise for a purely 262kHz watch!:roll:
> 
> ...


I have no idea what a little TC means. Could it be coarse temperature/counts tables?


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## ppaulusz (Feb 11, 2006)

ronalddheld said:


> I have no idea what a little TC means. Could it be coarse temperature/counts tables?


Yes, deliberately coarse by purpose!


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## wbird (Feb 25, 2015)

ppaulusz said:


> Be *WARNED* that the following thoughts are just speculations that means that I might have something here or I might be completely wrong...:-s
> 
> I do have a problem with my Bulova 262kHz watch: it is too accurate/precise for a purely 262kHz watch!:roll:
> 
> ...


Just a couple of thoughts, I don't think Seiko employed a tri-prong torsional oscillation approach in their HF movements. Hard to separate or determine how much this type of crystal and cut contributes to thermal insensitivity.

Prior to 2014 there were only 2 or 3, albeit animated posters, slamming the accuracy of these watches. Not many data points, and during that period folks also had a few Citizen's with issues, they were simply sent back for calibration with little emotion. In addition during that period one member talking about severe ageing. Haven't seen many if any other members confirming that.

Maybe citizen improved on these watches, or maybe we're just getting more data. Either way it's nice to see your watch is performing well, hope it meets your expectations for looks, fit, and finish as well.


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## ppaulusz (Feb 11, 2006)

wbird said:


> ...Prior to 2014 there were only 2 or 3, albeit animated posters, slamming the accuracy of these watches...


Do you suggest that because of "2 or 3, albeit animated posters" Bulova changed the specifications by taking out the "within 10 seconds/year" claim from the specs?
I'd think, it takes more than "2 or 3, albeit animated posters" to achieve that modification of the specifications.

You see, the above is not the speculation parts of my post (there are speculations in it but not this part about the early 262kHz models).
It is a fact that early Bulova 262kHz watches could not meet the "within 10 seconds/year" specification.
It is also a fact that Bulova does no longer use this "within 10 seconds/year" claim. In other words even Bulova admits that the claimed specifications cannot be met so the wording got rewritten!
It is also a fact that a tri-prong torsional oscillation approach was always part of the design of the 262kHz Bulova models even in the case of the early models and even that tri-prong torsional oscillation could not help those early models as they were nowhere near to the claimed specification.

Users' feedbacks strongly indicate improved accuracy-performance with later models of the Bulova 262kHz watches. On the other hand Bulova did not mention any technological advancement with those later models comparing to the earlier models. So we are left at our own to figure out what might have happened. I had a shot at it and shared with the forum members/visitors my theory/speculation. Anyone is welcome to argue (agree or disagree) with that or offer another answer/view.

However facts are facts! Let's not argue about facts! I'm happy if you are questioning my "speculation" about the improved accuracy performance of the later models. No problem with that but arguing about facts... it's rather pointless.


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## wbird (Feb 25, 2015)

ppaulusz said:


> Do you suggest that because of "2 or 3, albeit animated posters" Bulova changed the specifications by taking out the "within 10 seconds/year" claim from the specs?
> I'd think, it takes more than "2 or 3, albeit animated posters" to achieve that modification of the specifications.
> 
> You see, the above is not the speculation parts of my post (there are speculations in it but not this part about the early 262kHz models).
> ...


I'm pretty certain Bulova cares very little about the thoughts of an extremely small population on a sub-forum on WUS. I agree they would never change their specs based on a couple of opinions posted back in 2012. The point I was making was 2 or 3 animated posters tarnished the reputation on Bulova here.

The FACT is that between 2012 and 2014, most (more than twice as many people with those early models), were posting results that Bulova was meeting 10 spy specs, on that epic D Denny thread. The fact is my Bulova met those specs and in my case would continue to meet the 10 spy if I wore it more.

Unless you're meeting some specific purchase specification, like say a military requirement, specifications are mostly just marketing. Simply put if Bulova says high performance, and it sells as many watches as saying 10 spy, than say high performance and avoid any potential problems of say the 1 to 5% of watches that may have problems meeting specs due to the environment they are worn in for example. As far as I know they don't spec the Precisionist models at all anymore, nothing in my manual, or on the Bulova site.

The fact is I don't know how good or bad the Precisionist performed in the past or will routinely perform at the 95% confidence level in the future, maybe 10, maybe 20 spy. I do know, to answer that question, assuming 10000 watches sold and a failure rate of 1% I would need to randomly sample and test 101 watches based on mil spec sampling. The point is that we never had and still don't have enough data to say if they were that bad in the past, if they improved, or what Citizen/Bulova felt was an acceptable failure rate when the product was introduced, scaled up, and is now.

Just speculating but it would seem to me that Bulova has made incremental improvements in the manufacturing process and reduced the non conformance rate. That equates to more consistent products in the market, and lower probability of getting a 36 spy watch that D Dennys ranted about in 2012. Again just speculation on my part no better or worse than yours.


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## ppaulusz (Feb 11, 2006)

wbird said:


> I'm pretty certain Bulova cares very little about the thoughts of an extremely small population on a sub-forum on WUS. I agree they would never change their specs based on a couple of opinions posted back in 2012. The point I was making was 2 or 3 animated posters tarnished the reputation on Bulova here...


For me it was not the WUS people but Bulova itself who tarnished the reputation of Bulova as they were forced to change the specs. Why did Bulova change their specs, in your opinion? In my opinion, they changed it because people complained that the claimed accuracy was nowhere near to the real performance. Would you have a better explanation for the change?


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## Hans Moleman (Sep 24, 2007)

ppaulusz said:


> Be *WARNED* that the following thoughts are just speculations that means that I might have something here or I might be completely wrong...:-s
> 
> I do have a problem with my Bulova 262kHz watch: it is too accurate/precise for a purely 262kHz watch!:roll:
> 
> ...


A difference of 20 odd seconds per year between cold and warm is good, but not stellar.
Compare that with what dwjquest measured ages ago.

It is an achievement if its done without TC though.

You should buy lotto immediately. To pick a temperature where the rate is spot on, is nigh impossible.

What would impress me even more if you can do the same one year on. 
The fridge test should be great to pick up any off-the-chart aging.


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## ppaulusz (Feb 11, 2006)

Hans Moleman said:


> A difference of 20 odd seconds per year between cold and warm is good, but not stellar.
> Compare that with what dwjquest measured ages ago.
> 
> It is an achievement if its done without TC though.
> ...


Hans, that is exactly my point: "_*It is an achievement if its done without TC though*_."

Dave's tests were not as extreme as mine: he went from about 25 degree of Celsius to about 35 degree of Celsius a difference of about 10 degrees of Celsius (or 18 degrees of Fahrenheit).
I went from 4 degree of Celsius to 28 degree of Celsius a difference of about 24 degrees of Celsius (or 43 degrees of Fahrenheit), now that is much more extreme than Dave's and when you see the results you must wonder how could it be done without active thermocompensation?! *That is my point!*

Yes, both me and my Brother were laughing that it hit the sweet spot at exactly 4 degree of Celsius (what a fluke!) that my refrigerator was running on!:-!


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## ronalddheld (May 5, 2005)

Does anyone think it would be useful for me to buy a time only watch, and measure offsets for hopefully at least a decade?


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## ppaulusz (Feb 11, 2006)

ppaulusz said:


> Hans, that is exactly my point: "_*It is an achievement if its done without TC though*_."
> 
> Dave's tests were not as extreme as mine: he went from about 25 degree of Celsius to about 35 degree of Celsius a difference of about 10 degrees of Celsius (or 18 degrees of Fahrenheit).
> I went from 4 degree of Celsius to 28 degree of Celsius a difference of about 24 degrees of Celsius (or 43 degrees of Fahrenheit), now that is much more extreme than Dave's and when you see the results you must wonder how could it be done without active thermocompensation?! *That is my point!*...


In Dave's test one of the The Citizen (Cal.A660H) went from -6 seconds/year to -30 seconds/year, a difference of a massive 24 seconds (we are talking about Citizen's flagship quartz model!). His other The Citizen went from -2 seconds/year to -18 seconds/year, a difference of 16 seconds.
My Bulova went from 0 second/year to +15 seconds/year, a difference of 15 seconds only but over a much more extreme temperature-range!
All right, I know very well that Dave's and my tests' temperature-ranges were different still the Bulova seemingly did a much better job than the top-rated The Citizen... and did so officially without active thermocompensation! I think, I do have a pretty solid case here for a "_hidden-thermocompensation scheme_" regarding to my Bulova.


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## ronalddheld (May 5, 2005)

ppaulusz said:


> In Dave's test one of the The Citizen (Cal.A660H) went from -6 seconds/year to -30 seconds/year, a difference of a massive 24 seconds (we are talking about Citizen's flagship quartz model!). His other The Citizen went from -2 seconds/year to -18 seconds/year, a difference of 16 seconds.
> My Bulova went from 0 second/year to +15 seconds/year, a difference of 15 seconds only but over a much more extreme temperature-range!
> All right, I know very well that Dave's and my tests' temperature-ranges were different still the Bulova seemingly did a much better job than the top-rated The Citizen... and did so officially without active thermocompensation! I think, I do have a pretty solid case here for a "_hidden-thermocompensation scheme_" regarding to my Bulova.


Hidden coarse TC or new method of better Thermal insensitivity?


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## ronalddheld (May 5, 2005)

ppaulusz said:


> In Dave's test one of the The Citizen (Cal.A660H) went from -6 seconds/year to -30 seconds/year, a difference of a massive 24 seconds (we are talking about Citizen's flagship quartz model!). His other The Citizen went from -2 seconds/year to -18 seconds/year, a difference of 16 seconds.
> My Bulova went from 0 second/year to +15 seconds/year, a difference of 15 seconds only but over a much more extreme temperature-range!
> All right, I know very well that Dave's and my tests' temperature-ranges were different still the Bulova seemingly did a much better job than the top-rated The Citizen... and did so officially without active thermocompensation! I think, I do have a pretty solid case here for a "_hidden-thermocompensation scheme_" regarding to my Bulova.


Hidden coarse TC or new method of better Thermal insensitivity?


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## ppaulusz (Feb 11, 2006)

ronalddheld said:


> Hidden coarse TC or new method of better Thermal insensitivity?


If 262kHz by itself would be _that_ thermal insensitive then why did the watch companies in the 1970s go towards the power-hungry MHz-range?
I keep saying that 196kHz (Seiko) and 262kHz (Bulova) are just not thermo-insensitive enough by themselves to make serious accuracy claims based on their high-frequency alone. They are better than ordinary 32kHz quartz but not by a great margin. 
In case of Bulova, the later released 262kHz movements could be aided by a hidden coarse TC scheme (to save face for Bulova and Citizen but not directly challenging the high-end Citizen TC watches). That is my opinion and my measurements and the observations of other users are backing this argument... not to mention the laws of physics!;-)


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## ronalddheld (May 5, 2005)

Q claims the Laws of Physics are so inconvenient


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## Hans Moleman (Sep 24, 2007)

ronalddheld said:


> Does anyone think it would be useful for me to buy a time only watch, and measure offsets for hopefully at least a decade?


Wouldn't that be a lovely project!

Is must be detailed enough to see the hourly, daily, weekly, monthly, yearly and everything in between and beyond, variations.

That needs a computer to do the donkey work. And would take a few runs to get right.

Chris has done the year long VHP tests. Not a quick one-afternoon task.


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## wbird (Feb 25, 2015)

ppaulusz said:


> For me it was not the WUS people but Bulova itself who tarnished the reputation of Bulova as they were forced to change the specs. Why did Bulova change their specs, in your opinion? In my opinion, they changed it because people complained that the claimed accuracy was nowhere near to the real performance. Would you have a better explanation for the change?


I thought I was clear, as to why they revised or in the case of the Precisionist eliminated the spec. But again no HAQ watch can meet specifications in all environments and not all production will meet specs due to process variability. So I agree 100% will not meet specs. I disagree with your premise that none could or ever meet the spec. Mine did, and pretty much still does, and so do others.

Yes Bulova got and gets a bad reputation here. To this day I see folks quote one ageing rant, and that bad accuracy result from years back and disregard the contemporaneous and recent results that contradict those findings. Compare it to how Certina is treated.

With specs I think Bulova made a business decision. Is the 10 spy claim the main selling point or UHF, or the sweeping second hand, or all those dials? Even if 95 or 99% met specs why bother with the potential of 100's of complaints. That's why I think they made change, not because none could, but some couldn't, and it wouldn't affect sales.

As far thermal insensitivity, like I said I agree high frequency alone will not be enough to provide it. But a normal AT cut quartz watch will display a binomial curve of temperature versus precision, and the curve will shift with the change of angle of the cut. You could look at the graphs on an older TC thread. The angle and quality of the cut can result in a crystal operating in a pretty flat portion of the curve and be fairly stable across a temperature range. Good but not great.

Yet to see any similar data on the characteristics of the curve generated by a tri-prong movement. The nature of the tri-prong configuration may contribute to the thermal insensitivity. I also seem to remember that Bulova stated they incorporated some form of electronic correction for temperature when they introduced the watch.

Like I said I have a hard time figuring out how much frequency, crystal cut, crystal type, and TC factor into the accuracy and stability of a movement.


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## ronalddheld (May 5, 2005)

Hans Moleman said:


> Wouldn't that be a lovely project!
> 
> Is must be detailed enough to see the hourly, daily, weekly, monthly, yearly and everything in between and beyond, variations.
> 
> ...


Since I only take yearly measurements and do not have the needed tools, I will defer to others.


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## ppaulusz (Feb 11, 2006)

ppaulusz said:


> ...My Bulova went from 0 second/year to +15 seconds/year, a difference of 15 seconds only...


I should have thought about this "_in-refrigerator measurement_" a long time ago... Anyhow, it's better later than never...
Here is the next one: one of my top performer thermocompensated (rated within 10 seconds/year) watches from Citizen, Exceed (Cal.A715) from around 1997.
I subjected this Exceed to exactly the same tests as was the case with my Bulova (room temperature at 28 degree of Celsius off-wrist for 60 minutes and in-refrigerator at 4 degree of Celsius for 60 minutes - after 40 minutes of "cooling off" period) and here are the results:
- in the refrigerator after 60 minutes it run at -0,02 second/day or about -8 seconds/year
- at room temperature measuring for 60 minutes it run at +0,01 second/day or around +4 seconds/year
- a difference of 12 seconds only!
This top performing Exceed has beaten the Bulova by around 3 seconds (yearly scale!) in these extreme temperature-range (a difference of 24 degree of Celsius!) tests. 
This time it was apple vs apple regarding to the conditions - a better comparison than comparing it to Dave's results as his setup was different to mine.
This test again indicates that Bulova must be using some form of active thermocompensation with this 262kHz movement. The tests also indicate that the Exceed has a superior thermocompensation scheme as it has a standard 32kHz quartz vs 262kHz of the Bulova.
Well, it was fun to carry out these tests and for me they are very convincing.
Finally, here is the picture of my top performing Citizen Exceed (Cal.A715) - picture is from the net:


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## PetWatch (Nov 24, 2016)

I found this article by Matt Cunningham at howstuffworks.com "How the Bulova Precisionist Works", where he claims:

https://electronics.howstuffworks.com/gadgets/clocks-watches/bulova-precisionist3.htm

"Bulova engineers tackled the problem of temperature fluctuation by adding temperature regulation to the Precisionist's circuitry. The circuitry in the watch essentially senses temperature changes and adapts to corresponding changes in the quartz crystal's electric pulses. It's a small adjustment that might seem too miniscule to bother with, but tiny changes in pulse strength at the crystal's high oscillation frequency can add up to accuracy-killing deviations as the temperature changes [sources: Lombardi; DiFranco]."

Is there a simple, inexpensive way to test an IC for a thermo regulation component? Probably not or it would have been mentioned here, but why assume.


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## PetWatch (Nov 24, 2016)

ppaulusz said:


> I should have thought about this "_in-refrigerator measurement_" a long time ago... Anyhow, it's better later than never...
> Here is the next one: one of my top performer thermocompensated (rated within 10 seconds/year) watches from Citizen, Exceed (Cal.A715) from around 1997.
> I subjected this Exceed to exactly the same tests as was the case with my Bulova (room temperature at 28 degree of Celsius off-wrist for 60 minutes and in-refrigerator at 4 degree of Celsius for 60 minutes - after 40 minutes of "cooling off" period) and here are the results:
> - in the refrigerator after 60 minutes it run at -0,02 second/day or about -8 seconds/year
> ...


Once again thank you for all the testing and info, very informative, as well as everyone's comments.

I was going to mention the refrigerator after your first test but didn't want to be too intrusive, but since you seem to have taken a liking to it, do you have an oven? Willing to turn heater on or sweat outside on a hot day. It would be interesting to see results closer to body temp. Don't feel obliged.


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## ppaulusz (Feb 11, 2006)

PetWatch said:


> I found this article by Matt Cunningham at howstuffworks.com "How the Bulova Precisionist Works", where he claims:
> 
> https://electronics.howstuffworks.com/gadgets/clocks-watches/bulova-precisionist3.htm
> 
> ...


I was aware of this article but I deliberately ignored it. Why? Because of 2 reasons:
- I could not locate the real sources (sources: Lombardi; DiFranco) of the info
- I found this part in that article ridiculous (pay attention to the bolded parts): 
"The Precisionist uses a pair of tech tricks to overcome the quartz mechanism's weak points. First, its crystal is unique: most quartz watches use crystals shaped into two-pronged tuning forks, but the Precisionist literally goes one better with a three-pronged fork that the company claims *can oscillate at 262.144 kilohertz (or 16 beats per second)*, about eight times faster than *the 32.768 kilohertz (about 1 to 2 beats per second)* that is the typical frequency for quartz oscillators."
So the author managed to confuse himself with quartz frequency vs stepping motor beats... Not a trusted source... so to speak.;-)


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## ppaulusz (Feb 11, 2006)

PetWatch said:


> ...It would be interesting to see results closer to body temp...


You missed it! It's post #66 of this thread and its very first sentence:
"*I managed to carry out the on-wrist measurement (I had to use a rubber-band to fix the sensor to the watch on my wrist) and here is the result: the watch runs at +0,06 second/day or about at +22 seconds/year (on-wrist at room temperature of 28 degree of Celsius measured for 60 minutes and the watch had been worn for 10 hours before I started the measurement at this environment).*"

You can't get any closer to body temperature than this, can you?!


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## gaijin (Oct 29, 2007)

ppaulusz said:


> I should have thought about this "_in-refrigerator measurement_" a long time ago... Anyhow, it's better later than never...
> Here is the next one: one of my top performer thermocompensated (rated within 10 seconds/year) watches from Citizen, Exceed (Cal.A715) from around 1997.
> I subjected this Exceed to exactly the same tests as was the case with my Bulova (room temperature at 28 degree of Celsius off-wrist for 60 minutes and in-refrigerator at 4 degree of Celsius for 60 minutes - after 40 minutes of "cooling off" period) and here are the results:
> - in the refrigerator after 60 minutes it run at -0,02 second/day or about -8 seconds/year
> ...


This is very interesting work - thanks for posting it.

One point that bothers me, however, is it seems you are assuming that any rate changes or adjustments are applied almost instantaneously. By this I mean that it sounds like you are drawing the conclusion that the rate mesured after one hour (100 minutes including "cooling off" period) in your refrigerator test at 4 Deg C is the total adjustment that would be made for that temperature.

I think that the rate adjustments are probably applied in a much more subtle manner - probably taking several days to take full effect. My hypothesis is that if you were to leave your watches in the refrigerator for much longer - perhaps several days - you may see a much more significant change in measured rate.

This would be easy for you to test. It may even be a good idea to measure the rate in the refrigerator at 4 Deg C after 100 minutes (your current test), then after 24 hours, 48 hours, and so on to see if the rate is indeed changed quickly and maintained at that rate for several days, or if the rate continues to change over a period of several days.

Thanks again for your interesting work, and hope you might consider further testing at prolonged exposure to temperature changes.

As a side note, I was interested in the Horometer instrument you are using for your testing and I contacted Horometer directly to see if I could purchase one for my own testing. Unfortunately, they advised me that the developer of the Horometer product has died and they are not able to continue this product line. They also suggested that the accuracy of the Horometer, even when calibrated with the Rubidium oscillator calibrator, is around +1 Sec/Month or +12 Sec/Year. In view of that accuracy capability, the case is even stronger for repeated measurements over a longer period of time.

HTH


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## ppaulusz (Feb 11, 2006)

gaijin said:


> ...it seems you are assuming that any rate changes or adjustments are applied almost instantaneously. By this I mean that it sounds like you are drawing the conclusion that the rate mesured after one hour (100 minutes including "cooling off" period) in your refrigerator test at 4 Deg C is the total adjustment that would be made for that temperature.
> 
> I think that the rate adjustments are probably applied in a much more subtle manner - probably taking several days to take full effect. My hypothesis is that if you were to leave your watches in the refrigerator for much longer - perhaps several days - you may see a much more significant change in measured rate...


I don't necessary share your concern about the speed of the adjustments. It is not very life-like to subject the watch to 4 degree of Celsius for days. I compared 2 watches (Bulova and Exceed) by subjecting them to the same conditions and wanted to find out how would they react. That was all really.


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## ronalddheld (May 5, 2005)

Mr. Moderator appreciates those, who have taken the time and effort to quantify TC methods.
Maybe we need an ambitious soul to create a graph of offset versus temperature that I once saw for at least a GS?


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## Hans Moleman (Sep 24, 2007)

gaijin said:


> I was interested in the Horometer instrument


Search for 'timing machine'. I made my own before I realized they can be bought.
A Microset can be had for $1000. But even then, you need some persistence. From what I've heard.


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## ppaulusz (Feb 11, 2006)

gaijin said:


> ...As a side note, I was interested in the Horometer instrument you are using for your testing and I contacted Horometer directly to see if I could purchase one for my own testing. Unfortunately, they advised me that the developer of the Horometer product has died and they are not able to continue this product line. They also suggested that the accuracy of the Horometer, even when calibrated with the Rubidium oscillator calibrator, is around +1 Sec/Month or +12 Sec/Year. In view of that accuracy capability, the case is even stronger for repeated measurements over a longer period of time...


Yes, very sadly the developer of the Horometer has passed away...

When years ago he developed the first Horometer it was not capable of measuring high-accuracy quartz movements (only mechanical watches and standard quartz watches). I phoned him and asked him if he would be interested to make the necessary modification to it so that I could use it for my high-accuracy watches. To my pleasant surprise he was very co-operative and invited me to his office to discuss this would be development. He was a computer and electronics expert but not a watch expert not even a watch enthusiast. He thought that I was crazy (probably he was right) because my watch precision/accuracy mania. But he saw it as a challenge so we sorted out all the details and I got involved as well in the planning and testing. To cut a long story short, the Horometer became a professional high-precision quartz tester/analyzer within a couple of months. He listened to the GPS calibration proposal that replaced the Rubidium-based calibration unit (I purchased that Rubidium-based calibration unit from him that functions as a full-Horometer but not as portable as the Horometer - see the picture of it at the end of my post) and improved the internal quartz of the Horometer as well. His colleagues (very friendly and very smart team) were not involved in the development of the Horometer as the Horometer was not really their profile-project but rather a fun-project.

About the precision/accuracy of the Horometer: it is so stable and accurate/precise that after 6 months of non-calibrating it to the GPS it could not detect a difference between itself and the GPS on a 0,00 second/day-scale and that is all what we really need. My portable Horometer can be calibrated by the GPS and it delivers exactly the same results as my Rubidium-based one and only Horometer basestation. I hope that you can see from these info that the Horometer's internal clock is much more precise than the "around +1 Sec/Month or +12 Sec/Year" you were told.

Here is the picture of the one and only Rubidium-based Horometer basestation ("_5 minutes warm up_" written in Hungarian on the grey housing of the Rubidium timebase):


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## ppaulusz (Feb 11, 2006)

ppaulusz said:


> Yes, very sadly the developer of the Horometer has passed away...


He was also the one who modified my Seiko QM-10 Marine Chronometer:
https://www.watchuseek.com/f9/seiko-qm-10-quartz-marine-chronometer-steroid-3844170.html

So I'm eternally grateful to him and sadly miss him...


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## A2MI (Mar 26, 2016)

Very nice looking watch. It looks more expensive than it’s price. 
Not sure about the see through caseback though. Not much to see!


Sent from my iPhone using Tapatalk


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## gaijin (Oct 29, 2007)

ppaulusz said:


> Here is the picture of the one and only Rubidium-based Horometer basestation ("_5 minutes warm up_" written in Hungarian on the grey housing of the Rubidium timebase):












That looks like a completely different unit from the one you posted earlier:










:-s


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## PetWatch (Nov 24, 2016)

ppaulusz said:


> You missed it! It's post #66 of this thread and its very first sentence:
> "*I managed to carry out the on-wrist measurement (I had to use a rubber-band to fix the sensor to the watch on my wrist) and here is the result: the watch runs at +0,06 second/day or about at +22 seconds/year (on-wrist at room temperature of 28 degree of Celsius measured for 60 minutes and the watch had been worn for 10 hours before I started the measurement at this environment).*"
> 
> You can't get any closer to body temperature than this, can you?!


I was thinking in terms of the affects ambient temperature, which I believe you said was 28C, would have on the watch components internal temperature. I don't know if it's of any significance but equalizing the temperatures would eliminate this issue. May not be too hot where you are but in my are SoCal we are expecting 41C or higher this weekend. I don't plan on doing any outdoor watch testing for any period of time this weekend.


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## ppaulusz (Feb 11, 2006)

gaijin said:


> That looks like a completely different unit from the one you posted earlier:


The "Horometer" and the "Calibrator" on the top of the housing of the Rubidium timebase are permanently attached to it. That attached "Horometer" acts like a controlling module and physically/cosmetically looks like the earlier version of the Horometer (its software is very similar to the latest edition of the Horometer software) but it has no internal clock as it uses the Rubidium timebase from the grey Rubidium housing. That is a "Horometer on steroids" and less portable than the retail Horometer. There is only one of this ever made... this one!:-! 
Before the GSP calibration option was available that unit was the calibration source. 
The current retail Horometer has such a precise internal clock that it shows exactly the same measurements as the Rubidium timebased basestation Horometer even if I don't calibrate it with the GPS for months. Obviously, I'm talking about using the units at normal room-temperature.

Here is the picture of both units with my Bulova:


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## ppaulusz (Feb 11, 2006)

ppaulusz said:


> ...That is a "Horometer on steroids"...


Right now it is 30 degree of Celsius at room temperature and the Rubidium-based Horometer measures +0,05 second/day or about 18-19 seconds/year (off-wrist) after 60 minutes.
That is exactly in-line with my earlier measurements with the retail Horometer (see post #68 of this thread):
"..._as soon as the room temperature increased to 30 degree of Celsius, the running of the watch speeded up to +0,05 second/day or about +18 seconds/year_..."

So the retail Horometer is just as reliable as the one on steroid at any life-like environment.


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## sertse (Sep 30, 2012)

Why would a quartz crystal be cut so that it performs optimally at 4c? I thought the standard mantra is that watches are most accurate if worn constantly. 

Even without compensation having optimal performance at around the most realistically common temperature goes a long way.


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## ppaulusz (Feb 11, 2006)

sertse said:


> Why would a quartz crystal be cut so that it performs optimally at 4c? I thought the standard mantra is that watches are most accurate if worn constantly.
> 
> Even without compensation having optimal performance at around the most realistically common temperature goes a long way.


The cut of the quartz crystal is responsible for the thermal insensitivity of the quartz crystal or its running _*precision*_ over a certain temperature-range.
What you are _complaining_ about is the _*accuracy*_ of the calibration of the watch and it is digitally set at the factory and obviously it does not set individually for each quartz crystal. It is a matter of luck really but _*precision *_and _*accuracy*_ are two different things!
Making a precise watch is an art, making an accurate one is just a matter of luck and/or paying attention! The old Longines VHP models can be calibrated out of the factory as well. When I calibrate a Longines VHP I try to make it more accurate but I can't alter its precision!
If my Bulova would be equipped with a user adjustable digital calibration VHP-like interface I would be able to set its sweet spot wherever I want and it would not interfere with its precision but would be tailor-made for me (but not necessary for you as you might have a different environment).
If you were living in a cold place like Alaska spending long time outdoor you'd be quite happy with the accuracy of my Bulova...;-)


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## ppaulusz (Feb 11, 2006)

ppaulusz said:


> ...one of my top performer thermocompensated (rated within 10 seconds/year) watches from Citizen, Exceed (Cal.A715) from around 1997.
> I subjected this Exceed to exactly the same tests as was the case with my Bulova (room temperature at 28 degree of Celsius off-wrist for 60 minutes and in-refrigerator at 4 degree of Celsius for 60 minutes - after 40 minutes of "cooling off" period) and here are the results:
> - in the refrigerator after 60 minutes it run at -0,02 second/day or about -8 seconds/year
> - at room temperature measuring for 60 minutes it run at +0,01 second/day or around +4 seconds/year
> - a difference of 12 seconds only!...


One of my top performer thermocompensated (rated within 10 seconds/year) watches from Longines, Conquest VHP Perpetual Calendar (ETA 252.611) from around the year 2000.
I subjected this Longines VHP to exactly the same tests as was the case with my Bulova and Citizen Exceed (this time the room temperature at 30 degree of Celsius off-wrist for 60 minutes and in-refrigerator at 4 degree of Celsius for 60 minutes - after 40 minutes of "cooling off" period) and here are the results:
- in the refrigerator after 60 minutes it run at -0,02 second/day or about -8 seconds/year
- at room temperature measuring for 60 minutes it run at +0,01 second/day or around +4 seconds/year
- a difference of around 12 seconds only!

Note: though the room temperature was 2 degree of Celsius higher than in the case of the Exceed's test, the results were identical.

I think that with this test I completed the full circle: tested the Bulova CURV, the Citizen Exceed and the Longines Conquest VHP Perpetual Calendar models by subjecting them to extreme temperature-ranges in a fairly controlled environment. The thermocompensated giants (Exceed and Conquest) had finished neck-to-neck edging out the high-frequency Bulova CURV by a very small margin. I still tend to believe that the Bulova CURV got to have some form of hidden active thermocompensation as its results would indicate that.


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## Hans Moleman (Sep 24, 2007)

ppaulusz said:


> One of my top performer thermocompensated (rated within 10 seconds/year) watches from Longines, Conquest VHP Perpetual Calendar (ETA 252.611) from around the year 2000.
> I subjected this Longines VHP to exactly the same tests as was the case with my Bulova and Citizen Exceed (this time the room temperature at 30 degree of Celsius off-wrist for 60 minutes and in-refrigerator at 4 degree of Celsius for 60 minutes - after 40 minutes of "cooling off" period) and here are the results:
> - in the refrigerator after 60 minutes it run at -0,02 second/day or about -8 seconds/year
> - at room temperature measuring for 60 minutes it run at +0,01 second/day or around +4 seconds/year
> ...


I struggle to think of a method to prove thermo compensation.

What happened to your Witschi QTest 6000? You were measuring the quartz frequencies with it at some stage.


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## ppaulusz (Feb 11, 2006)

Hans Moleman said:


> I struggle to think of a method to prove thermo compensation.
> 
> What happened to your Witschi QTest 6000? You were measuring the quartz frequencies with it at some stage.


I sold the Witschi Q-Test 6000 as soon as I got the Horometer.
Measuring the quartz frequencies is trickier as most of the time it requires the opening of the back of the watch.
Horometer used to have quartz sensor option but I never purchased it and now it is no longer available.


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## ppaulusz (Feb 11, 2006)

Hans Moleman said:


> I struggle to think of a method to prove thermo compensation...


Hans, 24 degree of Celsius differences at the ends of the temperature-range are huge! It performs almost as good as the very bests over that temperature-range so it has to have some form of active thermocompensation... the laws of physics and common sense suggest this conclusion.;-)

Alright, let's turn the table: would you believe that the 262kHz Bulova with its special cut can perform according to my test results without active thermocompensation?!

Not a single test is available except mine with that extreme temperature-range. Forget the user reports for a moment as they never subjected their watches to these extreme conditions!


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## gaijin (Oct 29, 2007)

ppaulusz said:


> Not a single test is available except mine with that extreme temperature-range [24 degrees of Celsius]. Forget the user reports for a moment as they never subjected their watches to these extreme conditions!


I tested my X-33 at temperatures ranging from 43 DegF to 98 DegF (6 DegC to 37 DegC) - that's 31 degrees of Celsius difference. And that was prolonged exposure to those temperature extremes, not just a "temporary" exposure - and over a much longer period of time.

As you so aptly pointed out earlier, there is a big difference between precision and accuracy. Your testing measures precision at one point in time (about one hour), but shows nothing of accuracy over time. It is much different to say, "my watch runs at a rate of +10 Sec/Year for an hour" and to say, "my watch is +10 Seconds after a year."

HTH


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## Tom-HK (Jan 6, 2015)

ppaulusz said:


> Not a single test is available except mine with that extreme temperature-range. Forget the user reports for a moment as they never subjected their watches to these extreme conditions!


I have used an ex-lab heater/chiller in conjunction with a MicroSet timer to test watches from -5 to +40 Centigrade. Due to time and space constraints I have never had this as a regular set-up and I have not subjected a Bulova to the regime, but my DS-2, PSR-10 and The Citizen all survived the procedure and I am planning to revive the tests once circumstances better allow for it.


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## ppaulusz (Feb 11, 2006)

gaijin said:


> I tested my X-33 at temperatures ranging from 43 DegF to 98 DegF (6 DegC to 37 DegC) - that's 31 degrees of Celsius difference. And that was prolonged exposure to those temperature extremes, not just a "temporary" exposure - and over a much longer period of time.
> 
> As you so aptly pointed out earlier, there is a big difference between precision and accuracy. Your testing measures precision at one point in time (about one hour), but shows nothing of accuracy over time. It is much different to say, "my watch runs at a rate of +10 Sec/Year for an hour" and to say, "my watch is +10 Seconds after a year."
> 
> HTH


_*The subject of my tests was the Bulova CURV as the title of the thread indicates*_. All the other watches featuring in these tests were involved so we could appreciate the results of the Bulova CURV. The numbers _by themselves_ were not important as *I was interested whether the Bulova CURV performs/acts similarly or differently to the well known thermocompensated watches in these extreme temperature-ranges*. I've got the answer so the tests had achieved their purpose therefore they were successful. That is all no less, no more.


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## gaijin (Oct 29, 2007)

ppaulusz said:


> _*The subject of my tests was the Bulova CURV as the title of the thread indicates*_. All the other watches featuring in these tests were involved so we could appreciate the results of the Bulova CURV. The numbers _by themselves_ were not important as *I was interested whether the Bulova CURV performs/acts similarly or differently to the well known thermocompensated watches in these extreme temperature-ranges*. I've got the answer so the tests had achieved their purpose therefore they were successful. That is all no less, no more.


Well, that's all there is to say about that.


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## Hans Moleman (Sep 24, 2007)

> "my watch runs at a rate of +10 Sec/Year for an hour"
> "my watch is +10 Seconds after a year"


You've made a temperature controlled environment, and gave yourself the luxury to measure over long periods.

Without it there is a need to keep periods short, to keep temperature changes to a minimum.

Short periods require small measurement errors. An effect is then quickly visible. Hence the electronic measurement tools.

Extrapolation to a full year is for convenience only. You need to live in a cave to never experience temperature changes. The twenty degrees you've measure the rate at, won't persist for the rest of the year.


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## Hans Moleman (Sep 24, 2007)

ppaulusz said:


> Alright, let's turn the table: would you believe that the 262kHz Bulova with its special cut can perform according to my test results without active thermocompensation?!


Your logic is flawed.

An unproven theory is not deemed correct until proven false.

Here is an example:

Theory: The center of Mars contains a diamond.
Well? Anybody prove me wrong? Can't? I must be right then.

Sorry, it does not work that way.


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## ronalddheld (May 5, 2005)

Hans Moleman said:


> You've made a temperature controlled environment, and gave yourself the luxury to measure over long periods.
> 
> Without it there is a need to keep periods short, to keep temperature changes to a minimum.
> 
> ...


Moving to a cave or living several meters below ground would help my yearly samplings.


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## ppaulusz (Feb 11, 2006)

Hans Moleman said:


> Your logic is flawed.
> 
> An unproven theory is not deemed correct until proven false.
> 
> ...


Hans, I simply asked a question: _*Would you believe that the 262kHz Bulova with its special cut can perform according to my test results without active thermocompensation?!*_

I did not ask for proving anything, just a simple question of opinion that you could have answered _yes_ or _no_.
Instead of that you came up that my _logic is flawed_... Whose logic is flawed here? Mine or yours?

My question is still unanswered: Would you believe that the 262kHz Bulova with its special cut can perform according to my test results without active thermocompensation?! Yes or no? I'm after your opinion not your evidence/proof.


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## ronalddheld (May 5, 2005)

Please stick to technical issues.


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## DaveM (Aug 9, 2008)

ppaulusz said:


> Hans, 24 degree of Celsius differences at the ends of the temperature-range are huge! It performs almost as good as the very bests over that temperature-range so it has to have some form of active thermocompensation... the laws of physics and common sense suggest this conclusion.;-)


What on earth has common sense got to do with how thermally insensitive a crystal oscillator can be ?
Do the laws of physics provide a simple rule ?
I would not dogmatically close my mind to some innovation which will result in better thermal insensitivity.

Another important point, the mechanism of thermal compensation is very easy, I think that the real problem with current crystals is that a combination of matching (between crystals) and variability (over time) results in too much VARIATION of the thermal-error-characteristic to consistently achieve 5spy (= 1 part in 6million).
The first problem can be solved with money (calibrating every crystal), the second only by design and meticulous attention to detail.
It may be that higher frequency crystals are fundamentally more thermally stable, but I can understand ETA (or micro-crystal) sticking with 32Khz where they have decades of experience in making large numbers of low-drift crystals for minimal cost. I bet that achieving the theoretical stability (in parts-per-multimillion) in a production environment is largely down to lots of tiny, hard learned process details.

On older designs (original VHP perpetual) it is easy to check for TC.
I measure the time between watch-ticks and master-clock ticks using a Pico-scope and magnetic sensor (see the excellent post 'creating quartz-inhibition-measurement-tool').
I can see the drift at a normal-tick and the correction at an inhibition. For the old VHP I can see the inhibition compensating for the change in tick-period when I put my watch into a fridge (about 10C).

For the new VHP it is not so easy, the inhibition-mechanism is totally different, I am still trying to get my head round its principle and rationale.


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## ppaulusz (Feb 11, 2006)

DaveM said:


> What on earth has common sense got to do with how thermally insensitive a crystal oscillator can be ?
> Do the laws of physics provide a simple rule ?...


Who did mention common sense referring to how thermally insensitive a crystal oscillator can be?
Common sense was mentioned by me in relation to "_It performs almost as good as the very bests over that temperature-range so it has to have some form of active thermocompensation_..."

The laws of physics provide one simple rule even for a layman: _There is no miracle!_


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## BillSWPA (Feb 19, 2015)

With data points covering 19 days, my Sea King is averaging +0.03 sec./day. Temperature for the watch has been relatively constant.



Sent from my iPad using Tapatalk


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## wbird (Feb 25, 2015)

ppaulusz said:


> Hans, I simply asked a question: _*Would you believe that the 262kHz Bulova with its special cut can perform according to my test results without active thermocompensation?!*_
> 
> I did not ask for proving anything, just a simple question of opinion that you could have answered _yes_ or _no_.
> Instead of that you came up that my _logic is flawed_... Whose logic is flawed here? Mine or yours?
> ...


Yes, sure, why not? The point Hans was making is that just because it performs like a TC watch doesn't mean it has or uses it. It can but that would be just speculation. No better than saying a tri-prong cut quartz is thermally insensitive. That's just speculation too.

I haven't a clue, and neither do you, on wheather a tri-prong Bulova would require more, less, or any TC, compared to a conventional tuning fork AT cut quartz watch. All we know based on your testing is that the Bulova has pretty good precision across a broad temperature range.

How they achieve it is an open question, since you like to quote the laws of physics, the physics analogy would be Shroedingers cat in a box.


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## ronalddheld (May 5, 2005)

Maybe we need to think about how independent Bulova is from Citizen, in terms of share TC tech?


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## BillSWPA (Feb 19, 2015)

After 28 days my Sea King is still running at about +0.03 sec./day. 

This watch is so accurate that I think it will be at least another month or two before my own ability to touch my screen at exactly the right time becomes less of a factor. I am generally taking 3-5 data points in a row, and keeping only the one closest to the middle of the range of new data points.




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## fjblair (Apr 24, 2009)

Hans Moleman said:


> Quite unfortunate that a Bulova is even mentioned in a High Accuracy Forum.
> 
> For some that is endorsement enough.
> 
> That's the internet for ye!


Nonsense.


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## ronalddheld (May 5, 2005)

Please try to confine the discussion to technical issues.


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## Tomc1944 (Sep 21, 2009)

What a snob. Is everybody in New Zealand this way.


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## ronalddheld (May 5, 2005)

Mr. Moderator wants the personal attacks to stop.


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## BillSWPA (Feb 19, 2015)

After 50 days, my Sea King is exactly 2 seconds faster. This works out to 0.04 sec./day or 14.6 seconds per year. So, not quite within 10 sec./year but still very impressive. I still think that my ability to tap the screen at exactly the right time has partially skewed the results, and that more time may lessen the contribution of that factor to the variation recorded.

I am surprised because during the year I wore the watch daily, it ran a little slow rather than fast. Sitting in a drawer, it is now running a little fast.



Sent from my iPhone using Tapatalk


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## gh0stleader (Oct 4, 2017)

BillSWPA said:


> After 50 days, my Sea King is exactly 2 seconds faster. This works out to 0.04 sec./day or 14.6 seconds per year. So, not quite within 10 sec./year but still very impressive. I still think that my ability to tap the screen at exactly the right time has partially skewed the results, and that more time may lessen the contribution of that factor to the variation recorded.
> 
> I am surprised because during the year I wore the watch daily, it ran a little slow rather than fast. Sitting in a drawer, it is now running a little fast.
> 
> Sent from my iPhone using Tapatalk


love my chrono sea king!

- - - Updated - - -



BillSWPA said:


> After 50 days, my Sea King is exactly 2 seconds faster. This works out to 0.04 sec./day or 14.6 seconds per year. So, not quite within 10 sec./year but still very impressive. I still think that my ability to tap the screen at exactly the right time has partially skewed the results, and that more time may lessen the contribution of that factor to the variation recorded.
> 
> I am surprised because during the year I wore the watch daily, it ran a little slow rather than fast. Sitting in a drawer, it is now running a little fast.
> 
> Sent from my iPhone using Tapatalk


love my chrono sea king!


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## dannyking (Feb 9, 2013)

Awesome!


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