[time-nuts] 60hz disciplined watch

shalimr9 at gmail.com shalimr9 at gmail.com
Wed Apr 20 13:51:45 UTC 2011


Interesting, thank you!

Didier KO4BB

Sent from my BlackBerry Wireless thingy while I do other things...

-----Original Message-----
From: tom jones <epoch_time at yahoo.com>
Sender: time-nuts-bounces at febo.com
Date: Wed, 20 Apr 2011 06:43:25 
To: <time-nuts at febo.com>
Reply-To: Discussion of precise time and frequency measurement
	<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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