[time-nuts] 60hz disciplined watch

jmfranke jmfranke at cox.net
Wed Apr 20 14:10:39 UTC 2011


Do they detect the light flicker or the ambient ac field. Light flicker is 
120 Hz.

Very interesting,

John  WA4WDL

--------------------------------------------------
From: "tom jones" <epoch_time at yahoo.com>
Sent: Wednesday, April 20, 2011 9:43 AM
To: <time-nuts at febo.com>
Subject: [time-nuts] 60hz disciplined watch

> Most if not all Citizen ecodrive watches are disciplined by 60hz light 
> flicker that average
> the 60hz light flicker over approximately 10 days before a rate adjustment 
> is preformed.
>
> I have four citizen ecodrives;
>
> Plain jane quartz analogue ecodrive with mechanical calendar that is 60hz 
> disciplined.
>
> Stainless steel skyhawk ecodrive ana-digital that is 60hz disciplined. 
> I've monitored this one
> for over a week it was holding  13 miliseconds for over a weeks duration 
> (off the wrist mode) compaired to my cesium and ribidium references and 
> got distracted from futher measurements of this citizen skyhawk as I was 
> consumed with other measurements and comparisons between loran gps cesium 
> ribidium and other watches.
>
> Blue angles citizen skyhawk ana-digital that half the time seems to be 
> 60hz disciplined and other times unsure.
> This blue angles citizen skyhawk has the same movement as the stainless 
> steel skyhawk which is definately 60hz disciplined.
> I suspect this blue angles skyhawk that I purchased out of the country 
> could have 50hz and 60hz dicipline modes?
>
> My fourth citizen ecodrive is the stars & stripes forever yacht timer 
> ana-digital which is 60hz diciplined.
> This watch reboots every feb 28th at midnight to utc time zones and jan 1 
> 2004 (not sure of the exact year is crashes to) some kind of leap year 
> bug!
>
> Only unexpected temperature changes experienced by the ecodrive citizen 
> watches produce significant error
> (.5 to 1 second over several days of temperature varation) there rate will 
> correct after an approximate 10 day time constant.
>
> Many wrist watch forums make reference to citizen ecodrive rate accuratces 
> remarking that citizen uses some propriatary rate techniques. It's simply 
> 60hz light flicker received at the ecodrives solarbattery/photocell.
>
> I would recomend when setting your citizen ecodrive watches to set them 
> 2.5 to 3 seconds fast if worn continous because that is approximately how 
> much time will be lost before its rate gets compensated the first time.
>
> A Great Day to All , Tom
>
>
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