test

First change a battery. A DW-6630B was almost dead and we don't want it dead after one month. I forgot to reset, so it looked dead, but in fact the battery is complete full and fresh.

The GW-300, used to set all watches to atomic time.

Then I need them grouped in similar modules.

DW-069's and DW-6900. I consider these one of the coolest basic models, but they seem not very accurate.

DW-6600, also not particularly known about their accuracy.

Three different groups of DW-004/DW-6900E like models.

I forgot one G-2300, but now there are two basic blacks.

Masters of G: Gaussman, Frogman (GW-200) and Raysman. Very strange the similar models share two different modules

DW-003TL's normal and negative displays

DW-003S/DW-6900 models

New Mudman-s, I also included the GW-9000 with the auto receive turned off...

My Beloved DW-003's

DW-5600's

And when all set to atomic clock, all put in a big box for 30 days.

Results:

All watches were set to Atomic time (using a GW-300) on November 23, 2006. A Month is defined as 30 days, so end of test will be on December 22*.

model	color	module	seconds off per month	n	mean	σ(n-1)
DW-003X DW-003X DW-9000 DW-003 DW-004 DW-004 DW-004	Maroon Maroon Black White Maroon Red Yellow	1596 1596 1596 1596 1596 1596 1596	27 22 25 11 22 9 9	7	18	7.9
G-2300 G-2300 G-2300 G-2300	Red Sand Black Black	2184 2184 2184 2184	17 12 15 9	4	13	3.5
AW-571 AW-571 AW-571 AW-570	Black Black (old) Yellow trim M.I.Y.	1700 1700 1700 1700	8 10 9 13	4	10	2.2
DW-5600E DW-5600E DW-056	Red Black Black neg.	1545 1545 1545	38 32 13	3	28	13
GW-200 GW-200 GW-200 GW-200	Blue Black Gold Red	2422 2422 2422 2422	8 10 31 (?)** 13	3	10	2.5
DW-9300 DW-9300 DW-9300 DW09300	Black 20bar Black 20bar Black old Smoke	1803 1583 1803 1583	17 8 9 8	4	11	4.4
DW-003TL neg DW-003TL neg DW-003TL neg DW-003TL neg DW-003TL neg	Orange new Orange older Orange old White yellow/blue	1661 1661 1661 1661 1661	17 20 22 11 12	5	16	4.8
DW-003 Karate DW-003TL DW-003TL DW-003TL	White White Black Orange	1686 1686 1686 1686	29 14 24 35	4	26	8.9
DW-003S DW-003S DW-003S DW-003S DW-6900S	Yellow Green Red Green Blue/Green	1647 1647 1647 1647 1647	20 16 19 29 29	5	23	6.0
GW-9000 G-9000 G-9000 G-9000	Black Black White Green	3050 3031 3031 3031	-8 8 3 16	3***	9	6.6
DW-003HS DW-003 DW-003 DW-003 DW-003	Maroon Maroon Grey/khaki Black/khaki Green	1597 1597 1597 1597 1597	21 26 11 20 21	5	20	5.4
DW-069 DW-069 DW-069 DW-6900 DW-6900 DW-6900 DW-6900 DW-6900 DW-6900 DW-6900K	Beige Beige Beige Yellow Red Red Red Black Black (no retainer) Clear colorless	1289 1289 1289 1289 1289 1289 1289 1289 1289 1289	15 22 23 48 23 31 40 8 15 17	10	24	12.3
DW-6600 #13 DW-6630B DW-6630B DW-6630B DW-6630B	Black Yellow Yellow Yellow Purple	1198 1198 1198 1198 1198	47 23 13 16 26	5	25	13.4
DW-6900X DW-6900E DW-6900E DW-6900E BSB DW-6900X	Silver Silver/blue Silver Silver Bronze	1449 1449 1449 1449 1449	13 29 27 22 13	5	21	7.6
DW-004 DW-004X DW-004	Bronze Maroon Black	1825 1825 1825	-3 11 17	3	8	10.2

A average month is 265/12 = 30.4 days. The watches were synced in the morning of November 23rd and read in the evening of December 22nd, so that's close enough to 30½ days I think. * I consider this a spike. I never had problems with this model and as far as I know this one is much more accurate as what I found. *** The GW-9000 has the 3050 module.

Discussion:

For a real good test you need a pretty large load of the same modules at the time, so specially the tests with a few modules are of course very doubtful. I believe I forgot to set the Gold Defender Frog. I should double check that one.

Is a big σ a problem? No of course not. Casio says often a model is + or - 15 or 30 seconds of per month (I guess it's their 2σ point), so a σ around 7.5 is acceptable for most models, for the 30 seconds of modules 15 is acceptable.

The watches were kept in a relative warm room (my studio with quiet some warm equipment), approx 23ºC). A watch worn on wrist is warmer, so this might effect the quartz crystal.

As I expected the DW-6600, DW-6900 and DW-5600 don't come out to good. The biggest contradiction is found in the DW-003TL section. It looks like the 1661 and the 1686 module differ more than only a 90º twist of the polarization.

So does this test actually have worth....

Actually I don't think so, it's just fun playing with the numbers. I only had a crappy calculator around, so I had to calculate most σ(n-1)'s with just a pen and paper. Casio admits there is a pretty large allowance of the accuracy, but on the other hand. 30 sec's off per month is an accuracy of 30/2626560*100 = 0.0011%!

NOTE: Updated Sunday December 24th. Readers noticed a miscalculation. A 30.4 day month doesn't have 2635200 but 2626560 seconds. I accidentally multiplied by 30.5. All numbers are recalculated on a proper calculator. There appeared to be a miscalculation in the 1597 section. The mean was no 16, but 20, which resulted in a significantly smaller σ(n-1).

*A average month is 265/12 = 30.4 days. The watches were synced in the morning of November 23rd and read in the evening of December 22nd, so that's close enough to 30½ days I think.