PS

Perry Sandeen

Thu, Jan 27, 2011 8:55 PM

List,

I was reading some of the history of mechanical clocks and was astonished to see that one guaranteed its accuracy to 2 milliseconds per day! (And it was) Now this same clock when tested with modern equipment tested to be accurate to 200 micro-seconds per day. Astonishing!

This got to wondering how the heck they were able to calibrate a clock to milliseconds per day back then?

And as extension to that question, how do they prove the accuracy of F1 or other similar time standards?

Regards,

Perrier

List, I was reading some of the history of mechanical clocks and was astonished to see that one guaranteed its accuracy to 2 milliseconds per day! (And it was) Now this same clock when tested with modern equipment tested to be accurate to 200 micro-seconds per day. Astonishing! This got to wondering how the heck they were able to calibrate a clock to milliseconds per day back then? And as extension to that question, how do they prove the accuracy of F1 or other similar time standards? Regards, Perrier

BC

Brooke Clarke

Thu, Jan 27, 2011 8:57 PM

Hi Perrier:

When was this?
Do you have a URL?

Have Fun,

Brooke Clarke
http://www.PRC68.com

Perry Sandeen wrote:

List,

I was reading some of the history of mechanical clocks and was astonished to see that one guaranteed its accuracy to 2 milliseconds per day! (And it was) Now this same clock when tested with modern equipment tested to be accurate to 200 micro-seconds per day. Astonishing!

This got to wondering how the heck they were able to calibrate a clock to milliseconds per day back then?

And as extension to that question, how do they prove the accuracy of F1 or other similar time standards?

Regards,

Perrier

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 Perrier: When was this? Do you have a URL? Have Fun, Brooke Clarke http://www.PRC68.com Perry Sandeen wrote: > List, > > I was reading some of the history of mechanical clocks and was astonished to see that one guaranteed its accuracy to 2 milliseconds per day! (And it was) Now this same clock when tested with modern equipment tested to be accurate to 200 micro-seconds per day. Astonishing! > > This got to wondering how the heck they were able to calibrate a clock to milliseconds per day back then? > > And as extension to that question, how do they prove the accuracy of F1 or other similar time standards? > > Regards, > > Perrier > > > > > > _______________________________________________ > 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. > > >

PS

paul swed

Thu, Jan 27, 2011 9:13 PM

Boy I sure don't know but.
I could make some assumptions especially if it were 100 years ago. I might
guess its either a sun or star track and the fact that exactly 24 hours
later it crossed. Granted the clock could be adjusted so that its tick would
exactly cross. Most likely a light/candle and a small mirror on the
pendulum.... This would not account for any of the effects we consider
today. Just my crazy useless way of thinking.
Regards
Paul

On Thu, Jan 27, 2011 at 3:55 PM, Perry Sandeen sandeenpa@yahoo.com wrote:

List,

I was reading some of the history of mechanical clocks and was astonished
to see that one guaranteed its accuracy to 2 milliseconds per day! (And it
was) Now this same clock when tested with modern equipment tested to be
accurate to 200 micro-seconds per day. Astonishing!

This got to wondering how the heck they were able to calibrate a clock to
milliseconds per day back then?

And as extension to that question, how do they prove the accuracy of F1 or
other similar time standards?

Regards,

Perrier

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.

Boy I sure don't know but. I could make some assumptions especially if it were 100 years ago. I might guess its either a sun or star track and the fact that exactly 24 hours later it crossed. Granted the clock could be adjusted so that its tick would exactly cross. Most likely a light/candle and a small mirror on the pendulum.... This would not account for any of the effects we consider today. Just my crazy useless way of thinking. Regards Paul On Thu, Jan 27, 2011 at 3:55 PM, Perry Sandeen <sandeenpa@yahoo.com> wrote: > List, > > I was reading some of the history of mechanical clocks and was astonished > to see that one guaranteed its accuracy to 2 milliseconds per day! (And it > was) Now this same clock when tested with modern equipment tested to be > accurate to 200 micro-seconds per day. Astonishing! > > This got to wondering how the heck they were able to calibrate a clock to > milliseconds per day back then? > > And as extension to that question, how do they prove the accuracy of F1 or > other similar time standards? > > Regards, > > Perrier > > > > > > _______________________________________________ > 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. >

BC

Bob Camp

Thu, Jan 27, 2011 9:56 PM

Hi

If you go by Wikipedia, 10 ms per day was considered pretty good in 1909.
Shortt clocks came along in 1929 and are mentioned as 1 second per year. I
suspect the 2 ms / day and 1 sec per year numbers are both referring to a
Shortt.

Simple answer is that all of this came along after you had electronics to
compare stuff with. Calibration times were in months. Deviations between
clocks in an ensemble were used to estimate shorter time periods.

I don't find it to unbelievable that you could time an astronomical event to
~ 0.1 seconds or better without anything very fancy being involved. If you
wanted to automate it, light sensors date back into the 1850's. Either way
you could get data in less than a year that would confirm / deny your
accuracy.

Bob

-----Original Message-----
From: time-nuts-bounces@febo.com [mailto:time-nuts-bounces@febo.com] On
Behalf Of paul swed
Sent: Thursday, January 27, 2011 4:13 PM
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] Clock Calibration

Boy I sure don't know but.
I could make some assumptions especially if it were 100 years ago. I might
guess its either a sun or star track and the fact that exactly 24 hours
later it crossed. Granted the clock could be adjusted so that its tick would
exactly cross. Most likely a light/candle and a small mirror on the
pendulum.... This would not account for any of the effects we consider
today. Just my crazy useless way of thinking.
Regards
Paul

On Thu, Jan 27, 2011 at 3:55 PM, Perry Sandeen sandeenpa@yahoo.com wrote:

List,

I was reading some of the history of mechanical clocks and was astonished
to see that one guaranteed its accuracy to 2 milliseconds per day! (And it
was) Now this same clock when tested with modern equipment tested to be
accurate to 200 micro-seconds per day. Astonishing!

This got to wondering how the heck they were able to calibrate a clock to
milliseconds per day back then?

And as extension to that question, how do they prove the accuracy of F1 or
other similar time standards?

Regards,

Perrier

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 If you go by Wikipedia, 10 ms per day was considered pretty good in 1909. Shortt clocks came along in 1929 and are mentioned as 1 second per year. I suspect the 2 ms / day and 1 sec per year numbers are both referring to a Shortt. Simple answer is that all of this came along after you had electronics to compare stuff with. Calibration times were in months. Deviations between clocks in an ensemble were used to estimate shorter time periods. I don't find it to unbelievable that you could time an astronomical event to ~ 0.1 seconds or better without anything very fancy being involved. If you wanted to automate it, light sensors date back into the 1850's. Either way you could get data in less than a year that would confirm / deny your accuracy. Bob -----Original Message----- From: time-nuts-bounces@febo.com [mailto:time-nuts-bounces@febo.com] On Behalf Of paul swed Sent: Thursday, January 27, 2011 4:13 PM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] Clock Calibration Boy I sure don't know but. I could make some assumptions especially if it were 100 years ago. I might guess its either a sun or star track and the fact that exactly 24 hours later it crossed. Granted the clock could be adjusted so that its tick would exactly cross. Most likely a light/candle and a small mirror on the pendulum.... This would not account for any of the effects we consider today. Just my crazy useless way of thinking. Regards Paul On Thu, Jan 27, 2011 at 3:55 PM, Perry Sandeen <sandeenpa@yahoo.com> wrote: > List, > > I was reading some of the history of mechanical clocks and was astonished > to see that one guaranteed its accuracy to 2 milliseconds per day! (And it > was) Now this same clock when tested with modern equipment tested to be > accurate to 200 micro-seconds per day. Astonishing! > > This got to wondering how the heck they were able to calibrate a clock to > milliseconds per day back then? > > And as extension to that question, how do they prove the accuracy of F1 or > other similar time standards? > > Regards, > > Perrier > > > > > > _______________________________________________ > 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. > _______________________________________________ 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.

AM

Alan Melia

Thu, Jan 27, 2011 11:36 PM

Hi This is an interesting concept of measuring or comparing without
electronics. Dont forget the scientists of former eras has some quite
inovative bits of kit..... the CRT dated from the 1920 but Victorians used a
sooted glass slide carried on a small trolley that was moved by a falling
weight.....a storage 'scope forsooth :-)) I believe you will find Bell used
a similar item in his speech investigations. Also, yes time was cheaper then
so a test period of days would be acceptable......it only very recenly we
have become so impatient :-))
It would probably be relatively easy to divide the swing of a long pendulum
up in to 10ths or even 20th of a second ....and your reference would be a
transit telescope, or, I believe, the Moon and a church steeple ?? was that
Harrisons early work with the all wooden mechanisms?

Alan G3NYK

----- Original Message -----
From: "Bob Camp" lists@rtty.us
To: "'Discussion of precise time and frequency measurement'"
time-nuts@febo.com
Sent: Thursday, January 27, 2011 9:56 PM
Subject: Re: [time-nuts] Clock Calibration

Hi

If you go by Wikipedia, 10 ms per day was considered pretty good in 1909.
Shortt clocks came along in 1929 and are mentioned as 1 second per year. I
suspect the 2 ms / day and 1 sec per year numbers are both referring to a
Shortt.

Simple answer is that all of this came along after you had electronics to
compare stuff with. Calibration times were in months. Deviations between
clocks in an ensemble were used to estimate shorter time periods.

I don't find it to unbelievable that you could time an astronomical event

to

~ 0.1 seconds or better without anything very fancy being involved. If you
wanted to automate it, light sensors date back into the 1850's. Either way
you could get data in less than a year that would confirm / deny your
accuracy.

Bob

-----Original Message-----
From: time-nuts-bounces@febo.com [mailto:time-nuts-bounces@febo.com] On
Behalf Of paul swed
Sent: Thursday, January 27, 2011 4:13 PM
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] Clock Calibration

Boy I sure don't know but.
I could make some assumptions especially if it were 100 years ago. I might
guess its either a sun or star track and the fact that exactly 24 hours
later it crossed. Granted the clock could be adjusted so that its tick

would

exactly cross. Most likely a light/candle and a small mirror on the
pendulum.... This would not account for any of the effects we consider
today. Just my crazy useless way of thinking.
Regards
Paul

On Thu, Jan 27, 2011 at 3:55 PM, Perry Sandeen sandeenpa@yahoo.com

wrote:

List,

I was reading some of the history of mechanical clocks and was

astonished

to see that one guaranteed its accuracy to 2 milliseconds per day! (And

it

was) Now this same clock when tested with modern equipment tested to be
accurate to 200 micro-seconds per day. Astonishing!

This got to wondering how the heck they were able to calibrate a clock

to

milliseconds per day back then?

And as extension to that question, how do they prove the accuracy of F1

or

other similar time standards?

Regards,

Perrier

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.

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 This is an interesting concept of measuring or comparing without electronics. Dont forget the scientists of former eras has some quite inovative bits of kit..... the CRT dated from the 1920 but Victorians used a sooted glass slide carried on a small trolley that was moved by a falling weight.....a storage 'scope forsooth :-)) I believe you will find Bell used a similar item in his speech investigations. Also, yes time was cheaper then so a test period of days would be acceptable......it only very recenly we have become so impatient :-)) It would probably be relatively easy to divide the swing of a long pendulum up in to 10ths or even 20th of a second ....and your reference would be a transit telescope, or, I believe, the Moon and a church steeple ?? was that Harrisons early work with the all wooden mechanisms? Alan G3NYK ----- Original Message ----- From: "Bob Camp" <lists@rtty.us> To: "'Discussion of precise time and frequency measurement'" <time-nuts@febo.com> Sent: Thursday, January 27, 2011 9:56 PM Subject: Re: [time-nuts] Clock Calibration > Hi > > If you go by Wikipedia, 10 ms per day was considered pretty good in 1909. > Shortt clocks came along in 1929 and are mentioned as 1 second per year. I > suspect the 2 ms / day and 1 sec per year numbers are both referring to a > Shortt. > > Simple answer is that all of this came along after you had electronics to > compare stuff with. Calibration times were in months. Deviations between > clocks in an ensemble were used to estimate shorter time periods. > > I don't find it to unbelievable that you could time an astronomical event to > ~ 0.1 seconds or better without anything very fancy being involved. If you > wanted to automate it, light sensors date back into the 1850's. Either way > you could get data in less than a year that would confirm / deny your > accuracy. > > Bob > > -----Original Message----- > From: time-nuts-bounces@febo.com [mailto:time-nuts-bounces@febo.com] On > Behalf Of paul swed > Sent: Thursday, January 27, 2011 4:13 PM > To: Discussion of precise time and frequency measurement > Subject: Re: [time-nuts] Clock Calibration > > Boy I sure don't know but. > I could make some assumptions especially if it were 100 years ago. I might > guess its either a sun or star track and the fact that exactly 24 hours > later it crossed. Granted the clock could be adjusted so that its tick would > exactly cross. Most likely a light/candle and a small mirror on the > pendulum.... This would not account for any of the effects we consider > today. Just my crazy useless way of thinking. > Regards > Paul > > On Thu, Jan 27, 2011 at 3:55 PM, Perry Sandeen <sandeenpa@yahoo.com> wrote: > > > List, > > > > I was reading some of the history of mechanical clocks and was astonished > > to see that one guaranteed its accuracy to 2 milliseconds per day! (And it > > was) Now this same clock when tested with modern equipment tested to be > > accurate to 200 micro-seconds per day. Astonishing! > > > > This got to wondering how the heck they were able to calibrate a clock to > > milliseconds per day back then? > > > > And as extension to that question, how do they prove the accuracy of F1 or > > other similar time standards? > > > > Regards, > > > > Perrier > > > > > > > > > > > > _______________________________________________ > > 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. > > > _______________________________________________ > 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. > > > _______________________________________________ > 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.

CA

Chris Albertson

Thu, Jan 27, 2011 11:52 PM

On Thu, Jan 27, 2011 at 12:55 PM, Perry Sandeen sandeenpa@yahoo.com wrote:

...how the heck they were able to calibrate a clock to milliseconds per day back then?

Let it run for 1,000 days, then you only need to be able to measure to
the nearest second to get to ms per day. Or maybe you can measure to
0.1 seconds so it only takes 100 days.

The trouble is that using this method you don't know the average
error. A good example is an eccentric gear that makes a second hand
run fast then slow but if averaged over a long period is near perfect.
I doubt they were able to catch stuff like that.

--

Chris Albertson
Redondo Beach, California

On Thu, Jan 27, 2011 at 12:55 PM, Perry Sandeen <sandeenpa@yahoo.com> wrote: > ...how the heck they were able to calibrate a clock to milliseconds per day back then? Let it run for 1,000 days, then you only need to be able to measure to the nearest second to get to ms per day. Or maybe you can measure to 0.1 seconds so it only takes 100 days. The trouble is that using this method you don't know the average error. A good example is an eccentric gear that makes a second hand run fast then slow but if averaged over a long period is near perfect. I doubt they were able to catch stuff like that. -- ===== Chris Albertson Redondo Beach, California

S

scmcgrath@gmail.com

Sat, Jan 29, 2011 5:16 PM

Ah now from time nuttery to horology. There are those of us who tinker with analog clocks as well...

Generally we 'beat' clocks against 'standard' clocks or more recently a pc application with a microphone over long periods of time generally at least a week and commonly a month.

Scott
Sent from my Verizon Wireless BlackBerry

-----Original Message-----
From: Chris Albertson albertson.chris@gmail.com
Sender: time-nuts-bounces@febo.com
Date: Thu, 27 Jan 2011 15:52:49
To: Discussion of precise time and frequency measurementtime-nuts@febo.com
Reply-To: Discussion of precise time and frequency measurement
time-nuts@febo.com
Subject: Re: [time-nuts] Clock Calibration

On Thu, Jan 27, 2011 at 12:55 PM, Perry Sandeen sandeenpa@yahoo.com wrote:

...how the heck they were able to calibrate a clock to milliseconds per day back then?

Let it run for 1,000 days, then you only need to be able to measure to
the nearest second to get to ms per day. Or maybe you can measure to
0.1 seconds so it only takes 100 days.

The trouble is that using this method you don't know the average
error. A good example is an eccentric gear that makes a second hand
run fast then slow but if averaged over a long period is near perfect.
I doubt they were able to catch stuff like that.

--

Chris Albertson
Redondo Beach, California

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.

Ah now from time nuttery to horology. There are those of us who tinker with analog clocks as well... Generally we 'beat' clocks against 'standard' clocks or more recently a pc application with a microphone over long periods of time generally at least a week and commonly a month. Scott Sent from my Verizon Wireless BlackBerry -----Original Message----- From: Chris Albertson <albertson.chris@gmail.com> Sender: time-nuts-bounces@febo.com Date: Thu, 27 Jan 2011 15:52:49 To: Discussion of precise time and frequency measurement<time-nuts@febo.com> Reply-To: Discussion of precise time and frequency measurement <time-nuts@febo.com> Subject: Re: [time-nuts] Clock Calibration On Thu, Jan 27, 2011 at 12:55 PM, Perry Sandeen <sandeenpa@yahoo.com> wrote: > ...how the heck they were able to calibrate a clock to milliseconds per day back then? Let it run for 1,000 days, then you only need to be able to measure to the nearest second to get to ms per day. Or maybe you can measure to 0.1 seconds so it only takes 100 days. The trouble is that using this method you don't know the average error. A good example is an eccentric gear that makes a second hand run fast then slow but if averaged over a long period is near perfect. I doubt they were able to catch stuff like that. -- ===== Chris Albertson Redondo Beach, California _______________________________________________ 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.

NM

Neville Michie

Sat, Jan 29, 2011 11:55 PM

I have a little piezo sounder on the PPS from a t/bolt. It runs off a
cmos gate, I can not remember whether I put some pulse stretching in,
but it needs an on/off switch or the ticking will drive you mad.
This is great to use with the UTC time on LH. You look at the time,
then keep counting with the audible ticks to guide you while you
check your analogue clocks.
I also have a BCD counter dividing the 10MHz from the T/Bolt that
drives a time display. As well, the milliseconds, 100 microseconds,
or 10s of microseconds are counted and
can be latched by a proximity switch into a homebrew BCD DAC which is
recorded by a HOBO logger to give very accurate logging of phase for
whichever clock the proximity is clipped to.

It is all low power, saves serious frequency counters, PC et. al. so
you can log continuously for years without a major power bill.
cheers, Neville Michie

On 30/01/2011, at 4:16 AM, scmcgrath@gmail.com wrote:

Ah now from time nuttery to horology. There are those of us who
tinker with analog clocks as well...

Generally we 'beat' clocks against 'standard' clocks or more
recently a pc application with a microphone over long periods of
time generally at least a week and commonly a month.

Scott
Sent from my Verizon Wireless BlackBerry

-----Original Message-----
From: Chris Albertson albertson.chris@gmail.com
Sender: time-nuts-bounces@febo.com
Date: Thu, 27 Jan 2011 15:52:49
To: Discussion of precise time and frequency measurement<time-
nuts@febo.com>
Reply-To: Discussion of precise time and frequency measurement
time-nuts@febo.com
Subject: Re: [time-nuts] Clock Calibration

On Thu, Jan 27, 2011 at 12:55 PM, Perry Sandeen
sandeenpa@yahoo.com wrote:

...how the heck they were able to calibrate a clock to
milliseconds per day back then?

Let it run for 1,000 days, then you only need to be able to measure to
the nearest second to get to ms per day. Or maybe you can measure to
0.1 seconds so it only takes 100 days.

The trouble is that using this method you don't know the average
error. A good example is an eccentric gear that makes a second hand
run fast then slow but if averaged over a long period is near perfect.
I doubt they were able to catch stuff like that.

--

Chris Albertson
Redondo Beach, California

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.

I have a little piezo sounder on the PPS from a t/bolt. It runs off a cmos gate, I can not remember whether I put some pulse stretching in, but it needs an on/off switch or the ticking will drive you mad. This is great to use with the UTC time on LH. You look at the time, then keep counting with the audible ticks to guide you while you check your analogue clocks. I also have a BCD counter dividing the 10MHz from the T/Bolt that drives a time display. As well, the milliseconds, 100 microseconds, or 10s of microseconds are counted and can be latched by a proximity switch into a homebrew BCD DAC which is recorded by a HOBO logger to give very accurate logging of phase for whichever clock the proximity is clipped to. It is all low power, saves serious frequency counters, PC et. al. so you can log continuously for years without a major power bill. cheers, Neville Michie On 30/01/2011, at 4:16 AM, scmcgrath@gmail.com wrote: > Ah now from time nuttery to horology. There are those of us who > tinker with analog clocks as well... > > Generally we 'beat' clocks against 'standard' clocks or more > recently a pc application with a microphone over long periods of > time generally at least a week and commonly a month. > > Scott > Sent from my Verizon Wireless BlackBerry > > -----Original Message----- > From: Chris Albertson <albertson.chris@gmail.com> > Sender: time-nuts-bounces@febo.com > Date: Thu, 27 Jan 2011 15:52:49 > To: Discussion of precise time and frequency measurement<time- > nuts@febo.com> > Reply-To: Discussion of precise time and frequency measurement > <time-nuts@febo.com> > Subject: Re: [time-nuts] Clock Calibration > > On Thu, Jan 27, 2011 at 12:55 PM, Perry Sandeen > <sandeenpa@yahoo.com> wrote: > >> ...how the heck they were able to calibrate a clock to >> milliseconds per day back then? > > Let it run for 1,000 days, then you only need to be able to measure to > the nearest second to get to ms per day. Or maybe you can measure to > 0.1 seconds so it only takes 100 days. > > The trouble is that using this method you don't know the average > error. A good example is an eccentric gear that makes a second hand > run fast then slow but if averaged over a long period is near perfect. > I doubt they were able to catch stuff like that. > > > -- > ===== > Chris Albertson > Redondo Beach, California > > _______________________________________________ > 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. > _______________________________________________ > 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.

time-nuts@lists.febo.com

Clock Calibration

--

--

--