I've been running Debian for many years. During most of those years I
have had a SkyScan(tm) 'Atomic Clock' on the wall near my Debian
desktop computer. The physical computer has changed over the years,
but not my using Debian, or my Atomic Clock. Until a few weeks ago,
they always displayed the same time, once I had correctly installed
the chrony or the ntp package. But some time recently they started
disagreeing by about 18 seconds with Debian/Squeeze running ahead, yes
ahead, of the Atomic Clock which is supposedly getting its signal by
radio direclty from the NIST transmitter. How can this be???? I've
reinstalled the software, but that didn't change the behavior, except
for a brief period when the local computer clock resynchoronized with
the time server pool. There's nothing remarkable about my hardware.
An aging dual core pentium, marketed by HP and running Squeeze with
Gnome desktop. Ideas?
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Run cronyc and post the results of the "tracking" and "sources"
commands.
-- John Hasler
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> I've been running Debian for many years. During most of those years I
> have had a SkyScan(tm) 'Atomic Clock' on the wall near my Debian
> desktop computer. The physical computer has changed over the years,
> but not my using Debian, or my Atomic Clock. Until a few weeks ago,
> they always displayed the same time, once I had correctly installed
> the chrony or the ntp package. But some time recently they started
> disagreeing by about 18 seconds with Debian/Squeeze running ahead, yes
> ahead, of the Atomic Clock which is supposedly getting its signal by
> radio direclty from the NIST transmitter. How can this be???? I've
> reinstalled the software, but that didn't change the behavior, except
> for a brief period when the local computer clock resynchoronized with
> the time server pool. There's nothing remarkable about my hardware.
> An aging dual core pentium, marketed by HP and running Squeeze with
> Gnome desktop. Ideas?
Your Atomic Clock only resyncs once a day at about 3AM. Is it
possible that the mechanism of the clock is running slow during
the time after sync? I don't know if these clocks are crystal
controlled--if they are, then 18 seconds in a day would be quite
excessive. But if they're not, then perhaps something in the circuit
has aged out.
Alternatively, how often does your computer clock get resynchronized?
Maybe the circuit in the computer just runs fast?
--doug
-- Blessed are the peacekeepers...for they shall be shot at from both sides. --A.M. Greeley
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>>>>> Paul E Condon <pecon...@mesanetworks.net> writes:
>>>>> On 20121015_214840, John Hasler wrote:
>>>>> Paul E Condon writes:
>>> Ideas?
>> Run cronyc and post the results of the "tracking" and "sources"
>> commands.
> Now I am running NTP. Is there something I could post from NTP that
> would be useful?
$ ntpq -pn
> The switch will take some time, and I'd rather not do it now.
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> Run cronyc and post the results of the "tracking" and "sources"
> commands.
> -- > John Hasler
I've now switched to chrony. The offset between 'atomic clock' and
Gnome clock display remains greater than 15sec. Its hard to be more
precise because I can't get the clock and the computer in my field of
vision simultaneously. But, no way do they agree to anything like
under a second. I do have an always on connection to the internet, and
I did take care to remove the 'offline's from the chrony.conf.
root@big:/var/log/chrony# chronyc tracking
Reference ID : 204.235.61.9 (name1.glorb.com)
Stratum : 3
Ref time (UTC) : Tue Oct 16 05:47:52 2012
System time : 0.000000121 seconds fast of NTP time
Frequency : 190.723 ppm fast
Residual freq : -6.591 ppm
Skew : 2.035 ppm
Root delay : 0.099491 seconds
Root dispersion : 0.186323 seconds
root@big:/var/log/chrony# chronyc sources
210 Number of sources = 4
MS Name/IP address Stratum Poll LastRx Last sample
=========================================================================== =
^* name1.glorb.com 2 8 191 +1029us[ +950us] +/- 90ms
^+ d7.hotfile.com 2 8 184 +13ms[ +13ms] +/- 62ms
^? lttleman.deekayen.net 0 10 10y +0ns[ +0ns] +/- 0ns
^+ vpn.cumquat.nl 2 8 177 +17ms[ +17ms] +/- 103ms
root@big:/var/log/chrony#
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> On 20121015_214840, John Hasler wrote:
>> Paul E Condon writes:
>>> Ideas?
>> Run cronyc and post the results of the "tracking" and "sources"
>> commands.
>> -- >> John Hasler
> I've now switched to chrony. The offset between 'atomic clock' and
> Gnome clock display remains greater than 15sec. Its hard to be more
> precise because I can't get the clock and the computer in my field of
> vision simultaneously. But, no way do they agree to anything like
> under a second. I do have an always on connection to the internet, and
> I did take care to remove the 'offline's from the chrony.conf.
> root@big:/var/log/chrony# chronyc tracking
> Reference ID : 204.235.61.9 (name1.glorb.com)
> Stratum : 3
> Ref time (UTC) : Tue Oct 16 05:47:52 2012
> System time : 0.000000121 seconds fast of NTP time
> Frequency : 190.723 ppm fast
> Residual freq : -6.591 ppm
> Skew : 2.035 ppm
> Root delay : 0.099491 seconds
> Root dispersion : 0.186323 seconds
> root@big:/var/log/chrony# chronyc sources
> 210 Number of sources = 4
> MS Name/IP address Stratum Poll LastRx Last sample
> =========================================================================== =
> ^* name1.glorb.com 2 8 191 +1029us[ +950us] +/- 90ms
> ^+ d7.hotfile.com 2 8 184 +13ms[ +13ms] +/- 62ms
> ^? lttleman.deekayen.net 0 10 10y +0ns[ +0ns] +/- 0ns
> ^+ vpn.cumquat.nl 2 8 177 +17ms[ +17ms] +/- 103ms
> root@big:/var/log/chrony#
If you need very accurate time on the computer, you might want to
get a GPS receiver and download time from the satellites. (There must
be software somewhere on the 'net that will decode the GPS output.)
You'll need a serial port for the GPS data. The GPS antenna must be
outdoors.
A way to tell which source you're looking at is correct would be to
listen to WWV at 5, 10, or 15MHz on a short-wave receiver. You should
be able to receive one of these frequencies most any time of the
day or night. You'd need at least a moderate antenna, altho depending on
where you are, a whip on a short-wave receiver might work for one
of the frequencies, some time of the day.
At one time, you could get a time signal over the phone from the
Bell Telephone co.--now Verizon. Don't know if that's still possible.
I don't know if any of the time beeps on the broadcast radio stations
are accurate.
A receiver for WWVB at 60KHz that would decode the signals would be
as accurate as anyone could want. That's the signal that your "atomic"
clock receives, so the clock *should* be accurate. You might only be
able to receive the signal in the nighttime hours, like the clock.
Typically, the clock will sync up at about 2AM local time, and a WWVB
receiver would basically do the same thing, with an accurate crystal
oscillator as an internal reference to keep time when no signal is
being received. Such a receiver would probably cost over $1000,
at a guess, but that's the difference between a scientific reference
and a $20 "atomic" clock!
--doug
-- Blessed are the peacekeepers...for they shall be shot at from both sides. --A.M. Greeley
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> I've been running Debian for many years. During most of those years I
> have had a SkyScan(tm) 'Atomic Clock' on the wall near my Debian
> desktop computer. The physical computer has changed over the years,
> but not my using Debian, or my Atomic Clock. Until a few weeks ago,
> they always displayed the same time, once I had correctly installed
> the chrony or the ntp package. But some time recently they started
> disagreeing by about 18 seconds with Debian/Squeeze running ahead, yes
> ahead, of the Atomic Clock which is supposedly getting its signal by
> radio direclty from the NIST transmitter. How can this be????
I also like precise watches and have radio clocks in every room. Here
in continental Europe the radio clocks usually receive the DCF77 signal.
As written by others in this thread the clocks only synchronize once a
day to the signal. The rest of the day the clock is controlled by
crystal quartz which has a precision of +/- 1 minute/year.
My experience with radio clocks is that they have cheap electronic
components failing to work after some time. In the last 15 years I had
to throw away ~8 of them. Shortest lifetime was below 6 months,
longest 12 years. In your case I assume that the synchronization of
the clock isn't working any more since some months and it runs only
under control of the crystal quartz.
ntpd in the default debian configuration is usually accurate at +/- 2
ms.
You can use as root on the console terminal
# ntpq -p
remote refid st t when poll reach delay
offset jitter
= = = = = = ========================================================================
+dns2.teleport-i 73.120.242.92 2 u 562 1024 377 21.244
-3.468 1.467
-lswb-de-01.serv 95.211.148.1 3 u 746 1024 377 22.068 1.015 12.176
+78-159-107-102. 193.171.23.163 2 u 753 1024 377 34.084 2.664 47.216
*ntp3.rrze.uni-e .PPS. 1 u 403 1024 375 25.044
-1.860 1.541
Helmut Wollmersdorfer
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On Tue, Oct 16, 2012 at 02:59:37AM -0400, Doug wrote:
> On 10/16/2012 02:07 AM, Paul E Condon wrote:
> >On 20121015_214840, John Hasler wrote:
> >>Paul E Condon writes:
> >>>Ideas?
> >>Run cronyc and post the results of the "tracking" and "sources"
> >>commands.
> >>-- > >>John Hasler
> >I've now switched to chrony. The offset between 'atomic clock' and
> >Gnome clock display remains greater than 15sec. Its hard to be more
> >precise because I can't get the clock and the computer in my field of
> >vision simultaneously. But, no way do they agree to anything like
> >under a second. I do have an always on connection to the internet, and
> >I did take care to remove the 'offline's from the chrony.conf.
I notice here, that you're not actually reading the time from your
atomic clock. A local clock uses a pseudo IP address of "127.127.x.y"
(where x is a driver reference number and y is a clock instance number).
However, that shouldn't be a problem as, according to chrony you are
syncronised to within a tiny fraction of a second to the correct time.
Instead, I would suggest that it is your wall clock that is running
slow. Is there any sort of indicator on it which would tell you if the
radio signal is weak? 18 seconds sounds suspiciously like a GPS-time
offset, but I think that's a red-herring.
> >root@big:/var/log/chrony#
> A receiver for WWVB at 60KHz that would decode the signals would be
> as accurate as anyone could want. That's the signal that your "atomic"
> clock receives, so the clock *should* be accurate. You might only be
> able to receive the signal in the nighttime hours, like the clock.
> Typically, the clock will sync up at about 2AM local time, and a WWVB
> receiver would basically do the same thing, with an accurate crystal
> oscillator as an internal reference to keep time when no signal is
> being received. Such a receiver would probably cost over $1000,
> at a guess, but that's the difference between a scientific reference
> and a $20 "atomic" clock!
Sorry, did you just suggest that the solution for the OP's problem with
a radio controlled clock is... a radio controlled clock?
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Does Ntp agree with your wall clock?
-- John Hasler
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* Helmut Wollmersdorfer <helmut.wollmersdor...@fixpunkt.de> [121016 12:12]:
> My experience with radio clocks is that they have cheap electronic
> components failing to work after some time.
Unless you have more than one "atomic clock" and both agree,
the first thing to do is remove the battery from the clock for several
seconds, in order to force the clock to resynchronize. If the radio
receiver has ceased to function, the clock is not going to restart
until you press the BYPASS switch (at which time the clock is just
another quartz clock).
I agree with Helmut. Almost all of the "Sky Scan Atomic Clock" units
which I purchased over the years from Sam's Club (WalMart) appear to
be of very poor quality and short longevity. Only one or two still
are running, and on those the second hand stopped long ago.
RLH
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> Does Ntp agree with your wall clock?
> -- > John Hasler
No. It displays the same offset into the future in reference to the
SkyScan clock.
Also, I have escalated my effort on this. I actually have three(3)
Debian boxes, all showing 6.0.6 in /etc/debian-version. At the moment
two are running Ntp, and one is running chrony. All show the same
offset to as much precision as I can muster eyeballing to displays at
once visually. Could there have been a recent change in NIST broadcast
signalling standard that my rather old SkyScan is not handling
properly? Very unlikely, I know. But if I say that the Debian displays
of internet time are actually correct/true/whatever and the SkyScan is
confused, that explains the situation. But is that believable? I don't
think so, at least, not believable to this aging physicist who has had
knowledge of NIST since childhood when it was located inside
Washington, DC, and was called the Bureau of Standards. The facility
in Boulder did not yet exist then. There is a continuity of existence
that makes such a speculation silly to me. The info from the three systems:
root@gq:~# ntpq -pn
remote refid st t when poll reach delay offset jitter
=========================================================================== ===
+69.164.206.65 64.6.144.6 3 u 53m 1024 370 27.341 6.008 2.071
+69.122.22.85 209.51.161.238 2 u 50m 1024 374 97.619 16.028 3.403
*199.249.223.123 129.7.1.66 2 u 531 1024 377 35.028 -4.194 3.941
-24.149.253.214 208.90.144.53 3 u 493 1024 377 91.515 15.938 1.545
root@gq:~# less /etc/ntp.conf root@gq:~# cat /etc/debian_version 6.0.6
root@gq:~#
root@cmn:~# ntpq -pn
remote refid st t when poll reach delay offset jitter
=========================================================================== ===
+169.229.70.183 169.229.128.214 3 u 76 1024 377 42.350 0.786 4.726
*199.7.177.206 64.147.116.229 2 u 936 1024 377 23.638 -1.749 1.943
-50.116.45.175 150.233.214.204 3 u 39m 1024 4 80.487 -9.515 0.992
+67.18.187.111 129.7.1.66 2 u 35m 1024 4 23.162 -3.073 0.420
root@cmn:~# less /etc/ntp.conf root@cmn:~# cat /etc/debian_version 6.0.6
root@cmn:~# cat
root@big:~# chronyc tracking Reference ID : 204.235.61.9 (name1.glorb.com)
Stratum : 3
Ref time (UTC) : Tue Oct 16 13:02:17 2012
System time : 0.000000403 seconds fast of NTP time
Frequency : 191.966 ppm fast
Residual freq : 0.147 ppm
Skew : 0.350 ppm
Root delay : 0.071643 seconds
Root dispersion : 0.017760 seconds
root@big:~# chronyc sources
210 Number of sources = 4
MS Name/IP address Stratum Poll LastRx Last sample
=========================================================================== =
^* name1.glorb.com 2 10 688 +4900us[+6711us] +/- 63ms
^+ d7.hotfile.com 2 10 938 +10ms[ +12ms] +/- 64ms
^+ lttleman.deekayen.net 2 10 110 +6652us[+6652us] +/- 72ms
^+ vpn.cumquat.nl 2 10 675 +12ms[ +12ms] +/- 109ms
root@big:~# cat /etc/debian_version 6.0.6
root@big:~#
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> >I've been running Debian for many years. During most of those years I
> >have had a SkyScan(tm) 'Atomic Clock' on the wall near my Debian
> >desktop computer. The physical computer has changed over the years,
> >but not my using Debian, or my Atomic Clock. Until a few weeks ago,
> >they always displayed the same time, once I had correctly installed
> >the chrony or the ntp package. But some time recently they started
> >disagreeing by about 18 seconds with Debian/Squeeze running ahead, yes
> >ahead, of the Atomic Clock which is supposedly getting its signal by
> >radio direclty from the NIST transmitter. How can this be????
> I also like precise watches and have radio clocks in every room. Here
> in continental Europe the radio clocks usually receive the DCF77
> signal.
> As written by others in this thread the clocks only synchronize once
> a day to the signal. The rest of the day the clock is controlled by
> crystal quartz which has a precision of +/- 1 minute/year.
> My experience with radio clocks is that they have cheap electronic
> components failing to work after some time. In the last 15 years I
> had to throw away ~8 of them. Shortest lifetime was below 6 months,
> longest 12 years. In your case I assume that the synchronization of
> the clock isn't working any more since some months and it runs only
> under control of the crystal quartz.
> ntpd in the default debian configuration is usually accurate at +/- 2
> ms.
> You can use as root on the console terminal
> # ntpq -p
> remote refid st t when poll reach delay
> offset jitter
> =========================================================================== ===
> +dns2.teleport-i 73.120.242.92 2 u 562 1024 377 21.244
> -3.468 1.467
> -lswb-de-01.serv 95.211.148.1 3 u 746 1024 377 22.068
> 1.015 12.176
> +78-159-107-102. 193.171.23.163 2 u 753 1024 377 34.084
> 2.664 47.216
> *ntp3.rrze.uni-e .PPS. 1 u 403 1024 375 25.044
> -1.860 1.541
> Helmut Wollmersdorfer
I think you are mistaken about the sync only once a day. The signals
giving the year month and day are given once a day, but the precise
time-tics are given throughout the day. My clock has an indication
when it is receiving the radio signal which goes out when I move to a
place where the signal is weak, or when I change the battery and it
has not yet locked-in on the rhythm of the signal. Then, for a time,
the hour,minute,and second are good, but the date is wrong. Then after
a while, the correct date and day-of-week appear. I think the date
signal is actually more frequent than once a day, but definitely less
frequent than once a second. This is also the way that it is claimed
to work in the marketing materials.
The reason for my puzzlement is that the clock has always behaved in a
way consistent with the above --- for about twelve years starting when
I lived in California and continuing here in Colorado, where I now
live --- until recently when I noticed this 16sec offset. I have no
knowledge of international time signals. I'm sure there is world-wide
coordination, or perhaps the word is harmonization. Until quite
recently, it was very difficult to get information about the rest of
the world here in USA. Now more information appears to be available,
but I discount most of what I read because it appears to be false.
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> I think you are mistaken about the sync only once a day. The signals
> giving the year month and day are given once a day, but the precise
> time-tics are given throughout the day.
Well, in Europe the signal is indeed sent every second, but this doesn't mean that the my is actually using it. The clock itself is programed to synchronize only once per day, for the rest of the day relying on its internal (most probably cheap) clock.
Since the signal is quite weak here where I live (it also doesn't help that my apartment is oriented mostly towards south-east) the overnight sync doesn't always succeed so I have to move my clock to a specific place in the apartment and trigger a manual resync from time to time. For example, right now my radio clock was about 5 sec ahead.
>> A receiver for WWVB at 60KHz that would decode the signals would be
>> as accurate as anyone could want. That's the signal that your "atomic"
>> clock receives, so the clock *should* be accurate. You might only be
>> able to receive the signal in the nighttime hours, like the clock.
>> Typically, the clock will sync up at about 2AM local time, and a WWVB
>> receiver would basically do the same thing, with an accurate crystal
>> oscillator as an internal reference to keep time when no signal is
>> being received. Such a receiver would probably cost over $1000,
>> at a guess, but that's the difference between a scientific reference
>> and a $20 "atomic" clock!
> Sorry, did you just suggest that the solution for the OP's problem with
> a radio controlled clock is... a radio controlled clock?
A $1000 radio controlled clock--not a $20 one. As someone else suggested,
it is likely that the radio receiver in the cheap clock is no longer functioning, and
the crystal oscillator, which of necessity uses a cheap poor-tolerance crystal,
is running on its own, and drifting off frequency.
--doug
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> * Helmut Wollmersdorfer <helmut.wollmersdor...@fixpunkt.de> [121016 12:12]:
> > My experience with radio clocks is that they have cheap electronic
> > components failing to work after some time.
> Unless you have more than one "atomic clock" and both agree,
> the first thing to do is remove the battery from the clock for several
> seconds, in order to force the clock to resynchronize. If the radio
> receiver has ceased to function, the clock is not going to restart
> until you press the BYPASS switch (at which time the clock is just
> another quartz clock).
> I agree with Helmut. Almost all of the "Sky Scan Atomic Clock" units
> which I purchased over the years from Sam's Club (WalMart) appear to
> be of very poor quality and short longevity. Only one or two still
> are running, and on those the second hand stopped long ago.
> RLH
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There is a useful chart of available sources of time and the accuracy available
on page 11, table 1.1.
Problems in reception are discussed, especially on page 24, from
which I quote:
WWVB clocks like those you might find in a home or office are shown in Figure 2.10.
These clocks not only keep accurate time, but they automatically adjust for Daylight
Saving Time, leap seconds, and leap years. They work by synchronizing an inexpensive
quartz oscillator to the WWVB time code. The period of synchronization varies from
model to model, but many units synchronize only once every 24 hours; usually during the
evening when the signal is strongest. In between synchronizations, time is kept using the
quartz oscillator. Typically, the quartz oscillator can maintain frequency to within a few
parts per million, so it will take at least two or three days to gain or lose a full second even
if WWVB has not been received. Therefore, synchronizing once per day is usually enough
to keep a clock’s display on the right second. If you live within the coverage area and
your WWVB clock is unable to synchronize, it usually means a source of radio interference
is near the receiver. Some common culprits are computer monitors (some have a
scan rate at or very close to 60 kHz), noisy AC wiring, fluorescent lamps, or nearby power
lines, transformers, or radio transmitters.
--doug
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I just tried name1.glorb.com. It is distributing correct time and your
machine is synchronizing properly to it. Your wall clock is broken. -- John Hasler
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On Tue, 2012-10-16 at 12:54 -0400, Doug wrote:
> It is instructive to look at the NIST website that discusses the time
> standards and the broadcasting of the time.
> There is a useful chart of available sources of time and the accuracy > available
> on page 11, table 1.1.
In the old day clocks were synced by mains frequency. Mains frequency in
western industrialized countries usually is very accurate. :p
I know a nice anecdote of very inaccurate mains frequency from an
US-American engineer and I experienced inaccurate mains frequencies in
western Germany myself, but in general at least crystal clocks aren't
accurate, perhaps clocks synced by mains might be more accurate, I don't
know. Regarding to sync via air, I experienced that a DVB-T receiver I
own, very often get no signal to sync. I guess crystal clocks fail
regarding to temperature swings.
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To add to my previous post, re WWV: you can still hear the
radio station by telephone. the website I cited before can
be reached, as reported:
To hear these broadcasts, dial (303) 499-7111 for WWV and (808) 335-4363 for WWVH.
You can listen for about two minutes before your call is disconnected. Please keep in
mind that these are not toll-free numbers. Callers outside the local calling area are
charged long distance rates.
--doug
-- Blessed are the peacekeepers...for they shall be shot at from both sides. --A.M. Greeley
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On Tue, Oct 16, 2012 at 11:49:19AM -0400, Doug wrote:
> >>A receiver for WWVB at 60KHz that would decode the signals would be
> >>as accurate as anyone could want. That's the signal that your "atomic"
> >>clock receives, so the clock *should* be accurate. You might only be
> >>able to receive the signal in the nighttime hours, like the clock.
> >>Typically, the clock will sync up at about 2AM local time, and a WWVB
> >>receiver would basically do the same thing, with an accurate crystal
> >>oscillator as an internal reference to keep time when no signal is
> >>being received. Such a receiver would probably cost over $1000,
> >>at a guess, but that's the difference between a scientific reference
> >>and a $20 "atomic" clock!
> >Sorry, did you just suggest that the solution for the OP's problem with
> >a radio controlled clock is... a radio controlled clock?
> A $1000 radio controlled clock--not a $20 one. As someone else suggested,
> it is likely that the radio receiver in the cheap clock is no longer
> functioning, and
> the crystal oscillator, which of necessity uses a cheap
> poor-tolerance crystal,
> is running on its own, and drifting off frequency.
Unplug / remove the battery of the wall clock for a while, then plug it back in and see if it resets its time. That'll tell you if the receiver
is working.
-Rob
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> I think you are mistaken about the sync only once a day. The signals
> giving the year month and day are given once a day, but the precise
> time-tics are given throughout the day. My clock has an indication
> when it is receiving the radio signal which goes out when I move to a
> place where the signal is weak, or when I change the battery and it
> has not yet locked-in on the rhythm of the signal. Then, for a time,
> the hour,minute,and second are good, but the date is wrong. Then after
> a while, the correct date and day-of-week appear. I think the date
> signal is actually more frequent than once a day, but definitely less
> frequent than once a second. This is also the way that it is claimed
> to work in the marketing materials.
Maybe you have a better radio clock, but most the cheap ones (20 - 40
EUR/USD) sync once a day, or on demand by reset.
The process is as follows:
1. The sender emits the signal as a pulse every second (low or high bit)
2. The bits sent in one minute (59, 60 or 61 seconds) form a full
record containing date, time, daylight saving, leap year, leap seconds
and other information
3. The antenna of your clock receives the signal and tries to get the
complete information of a cycle. This can need many minutes if the
signal is noisy. Or it can fail. Or it only works in the night because
of 'noise'.
4. The clock tries to move the clockhands in the correct position, and/ or tries to set the displays for date, weekday, and second.
The last two radio clocks I threw away had problems with step 4. They
synced after reset (I tried often and also changed batteries, cleaned
the contacts etc.), but the clockhands stopped at wrong positions. And
it always was the same offset.
> The reason for my puzzlement is that the clock has always behaved in a
> way consistent with the above --- for about twelve years starting when
> I lived in California and continuing here in Colorado, where I now
> live --- until recently when I noticed this 16sec offset.
Your wallclock is out of order.
If you want to know it for sure, you can build a receiver for the
signal, connect it to your computer and configure it into ntpd. There
is enough documentation and software available for free about this.
The material for one receiver costs around 10-20 USD. In my best time
I had two time-servers with 6 such receivers connected to the servers.
They received the British, Swiss and German time signals.
> I have no
> knowledge of international time signals. I'm sure there is world-wide
> coordination, or perhaps the word is harmonization.
Time is coordinated internationally since more than 100 years. Each
country has its own metrologic institute coordinating the time with
the central bureau AFAIK in Paris. You can read everything about it in
the internet.
If and since when the US take part of this coordination--I don't know.
The US do not like international agreements. Have the US signed the
Human Rights, or the international Woman Rights?
Helmut Wollmersdorfer
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> If you live within the coverage area and
> your WWVB clock is unable to synchronize, it usually means a source
> of radio interference
> is near the receiver. Some common culprits are computer monitors
> (some have a
> scan rate at or very close to 60 kHz), noisy AC wiring, fluorescent
> lamps, or nearby power
> lines, transformers, or radio transmitters.
Also large soundboxes, machinery can disturb the signal.
I also experienced an unusual problem (because its unusual to have so
many receivers): I positioned 3 receivers with antennas tuned to the
same frequency in a line with a small distance between them. Then they
disturbe each other. Around 10 cm (4 inches) distance between them
solved the problem.
Helmut Wollmersdorfer
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On Wed, 2012-10-17 at 09:49 +0200, Helmut Wollmersdorfer wrote:
> cheap ones (20 - 40 EUR/USD)
Radio-controlled table clocks cost less than 9,- EUR some time ago, at a
German discounter.
End of 2009 I bought a power meter for 9.99 EUR from a German
discounter. I've got reasonable doubt that the measuring accuracy is
that exact as the specifications do claim.
The scientific pocket calculator I bought from discounters always failed
very soon, but they are able to do everything an expensive scientific
calculator from the stone age I own can do, while being 30 times
cheaper. Today's branded calculators that perhaps can do more, are
around 8 times more expensive. I don't know how long those do last.
Discounters sell crap.
YMMV,
Ralf
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