This looks good! http://www.ablogtoread.com/citizen-satellite-eco-drive-watch-gets-time-from-space/ At 21-04-2011, you wrote: >Group, > >Google can't find anything for "citizen ecodrive watch time sync 60 hz" >except a few where the "k" was left out of "60 khz". All of the watches >that synched received WWVB at 60 KHz. -- Raj, VU2ZAP Bangalore, India.

Ouch, $3k! My $50 watch that talks to WWVB does just as good a job when measuring it with my eye. -Bob On Wed, Apr 20, 2011 at 11:01 PM, Raj <vu2zap@gmail.com> wrote: > This looks good! > > > http://www.ablogtoread.com/citizen-satellite-eco-drive-watch-gets-time-from-space/ > > At 21-04-2011, you wrote: > >Group, > > > >Google can't find anything for "citizen ecodrive watch time sync 60 hz" > >except a few where the "k" was left out of "60 khz". All of the watches > >that synched received WWVB at 60 KHz. > > -- > Raj, VU2ZAP > Bangalore, India. > > > _______________________________________________ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. >

Hi, I think this is incorrect, 1/ My ecodrive that I bought in the USA does not run 20% slow here in the UK 2/What about incandesent lamps and those with inverters? 3/ even a cheap crysal is better than than the mains unless you average over days. They vary the frequency (phase) slightly to load share.   Robert G8RPI. --- On Wed, 20/4/11, Bill Hawkins <bill@iaxs.net> wrote: From: Bill Hawkins <bill@iaxs.net> Subject: Re: [time-nuts] 60hz disciplined watch (really?) To: "'Discussion of precise time and frequency measurement'" <time-nuts@febo.com> Date: Wednesday, 20 April, 2011, 19:33 Group, Google can't find anything for "citizen ecodrive watch time sync 60 hz" except a few where the "k" was left out of "60 khz". All of the watches that synched received WWVB at 60 KHz. The claim of 13 millisecond accuracy from line frequency is suspect. There is no control of the power grid to that accuracy. It is not possible. The weekly accuracy is measured in cycles. Variation during the day can be seconds, losing during the day and gaining at night. It seems to me that the filtering algorithm for 60 Hz would have severe underflow problems with floating point math in a low power processor. Bill Hawkins _______________________________________________ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.

In message <op.vt8v9bt2unbdei@indignity.dillberg.com>, "Christian Vogel" writes : It may be different in the NordPool area, but my measurements do not indicate much interest in time-stability here. Even if it did, I see no way your wrist-watch could use it, given that you need very long integration times, and the phase any one lightbulb is on is random between 0 and 360 degrees. (due to three phases and transformer-design) -- Poul-Henning Kamp | UNIX since Zilog Zeus 3.20 phk@FreeBSD.ORG | TCP/IP since RFC 956 FreeBSD committer | BSD since 4.3-tahoe Never attribute to malice what can adequately be explained by incompetence.

Robert Atkinson wrote: > Hi, > I think this is incorrect, > 1/ My ecodrive that I bought in the USA does not run 20% slow here in the UK > 2/What about incandesent lamps and those with inverters? > As has been pointed out in an earlier post detecting the second harmonic modulation in the light output of an incandescent lamp powered by a 50Hz or 60Hz source is trivially easy, one can even detect it with an LED. > 3/ even a cheap crysal is better than than the mains unless you average over days. They vary the frequency (phase) slightly to load share. > > Robert G8RPI. > --- On Wed, 20/4/11, Bill Hawkins<bill@iaxs.net> wrote: > > > Bruce

Fascinating. 1. Does anyone know if they have different models for 50 and 60 Hz regions (or is the internal software smart enough to differentiate)? 2. Any else think this is a questionable approach for a watch that is heavily advertised (at least around here) as being great for the boating set? If they have lights, they are usually DC...imagine being on a nice long distance yacht voyage, and your watch (highly accurate at home) just gets worse and worse as the days go on. 3. Based on the industrial frequency meter I have on our power line here in RI (US), the absolute frequency never varies more than +/- 0.04 Hz, and my Heathkit clock (uses the power line for timekeeping) never varies more than 4 seconds from the GPS based clock sitting next to it. On a trip to Scotland, using the same meter, I observed variations as large as +/- 0.1 Hz (not a typo, from 49.90 to 50.10 Hz). FWIW Tom Frank, KA2CDK On Apr 20, 2011, at 9:43 AM, tom jones wrote: > 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 > > > _______________________________________________ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there.