I now have a clock accurate to 10E-6!!!
Hi Folks,
Well I've had the best weekend since I've just acquired a pendulum clock
that used to be a telecommunication time standard in the 50s. It is a German
made Siemens pendulum master clock that is about 150cm high and has a
full-length seconds pendulum which is about a metre long. It is powered by
48V to automatically wind the weight up and will maintain time for about 8
hours without power.
The pendulum has an adjustment to raise and lower the 7.5kg weight to
calibrate the clock. One full turn of this knob will advance or retard the
clock by 40 seconds per day. It is graduated into 100 divisions enabling you
to adjust it within 0.4 seconds per day. Half way up the pendulum is a
little tray where you can deposit small weights for your final adjustment
(and most importantly without stopping the pendulum!)
Even though it's a master clock it is also designed to be synchronised to
another master clock and so there is an armature on the pendulum that can be
steered by a magnetic coil. I have no documentation on this bit, but when I
figure it out I naturally shall be driving it from a 1PPS reference. (See
photo.)
There are numerous contacts that are designed to open/shut at various times
including every second, every thirty seconds and minute. The photo shows the
mechanism behind the clock face.
By connecting the seconds contact up to my 5370B I tuned it quite quickly to
be accurate to about a second a day. Which is about 10 microseconds per
pendulum swing! I'm impressed a tick tock clock can do that. (Although it
pales into insignificance compared to what Harrison accomplished.)
It is beautifully constructed and now one of my prized possessions!
(I'll put some more photos in another post.)
Regards,
Jim
Here's an an extra photo showing the clock mechanism after the face and
hands have been removed.
Jim
And one more showing the coil that steers the pendulum.
Congratulation Jim, you really have a nice pendulum!!!
pf
(Pierre-François)
F5BQP
----- Original Message -----
From: "Jim Palfreyman" jim77742@gmail.com
To: "Discussion of precise time and frequency measurement"
time-nuts@febo.com
Sent: Monday, August 25, 2008 10:01 AM
Subject: Re: [time-nuts] I now have a clock accurate to 10E-6!!!
And one more showing the coil that steers the pendulum.
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Jim Palfreyman wrote:
Here's an an extra photo showing the clock mechanism after the face and
hands have been removed.
Jim
Almost identical to the master clock(s) that were used to synchronise
the British Railways station clocks in about 1980. A 48v 1pps was
distributed by private wire to many stations and platforms. Keeping all
of the clocks in synch was a full time job.
As a young hard up engineer I recall being quite jealous of the engineer
who got paid overtime twice a year to manually do the daylight saving
correction :-)
It was replaced by a new system with digital displays on the platforms
and I kicked myself years later for not keeping one of the old pulse
clocks for posterity.
Regards Paul
--
73 de Paul GW8IZR IO73TI
http://www.gw8izr.com
Jim;
Congratulations, that is a really nice looking clock!
You may have a real gem there. While the movement doesn't look like
anything special, the pendulum looks like a Riefler.
Which is something quite special...sort of like having a Thunderbolt
inside your bedside alarm clock...
Tom Frank
On Aug 25, 2008, at 3:40 AM, Jim Palfreyman wrote:
Hi Folks,
Well I've had the best weekend since I've just acquired a pendulum
clock
that used to be a telecommunication time standard in the 50s. It is
a German
made Siemens pendulum master clock that is about 150cm high and has a
full-length seconds pendulum which is about a metre long. It is
powered by
48V to automatically wind the weight up and will maintain time for
about 8
hours without power.
The pendulum has an adjustment to raise and lower the 7.5kg weight to
calibrate the clock. One full turn of this knob will advance or
retard the
clock by 40 seconds per day. It is graduated into 100 divisions
enabling you
to adjust it within 0.4 seconds per day. Half way up the pendulum is a
little tray where you can deposit small weights for your final
adjustment
(and most importantly without stopping the pendulum!)
Even though it's a master clock it is also designed to be
synchronised to
another master clock and so there is an armature on the pendulum
that can be
steered by a magnetic coil. I have no documentation on this bit,
but when I
figure it out I naturally shall be driving it from a 1PPS
reference. (See
photo.)
There are numerous contacts that are designed to open/shut at
various times
including every second, every thirty seconds and minute. The photo
shows the
mechanism behind the clock face.
By connecting the seconds contact up to my 5370B I tuned it quite
quickly to
be accurate to about a second a day. Which is about 10 microseconds
per
pendulum swing! I'm impressed a tick tock clock can do that.
(Although it
pales into insignificance compared to what Harrison accomplished.)
It is beautifully constructed and now one of my prized possessions!
(I'll put some more photos in another post.)
Regards,
Jim<IMGP4585.jpg>_______________________________________________
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.
On Mon, 25 Aug 2008 17:40:14 +1000, "Jim Palfreyman" jim77742@gmail.com
wrote:
Hi Folks,
Well I've had the best weekend since I've just acquired a pendulum clock
that used to be a telecommunication time standard in the 50s.
Nice.
I'd love to have a photo of that with both the clock and the rack of HP
goodies both showing. Move to the right a little, maybe use a tripod and turn
off the flash to get more uniform lighting and the result would be a wonderful
contrast between old and new.
John
John De Armond
See my website for my current email address
http://www.neon-john.com
http://www.johndearmond.com <-- best little blog on the net!
Tellico Plains, Occupied TN
fas-cism (fash'iz'em) n. A system of government that exercises a
dictatorship of the extreme right, typically through the
merging of state and business leadership, together
with belligerent nationalism. -- The American Heritage Dictionary, 1983
Yes the pendulum is a 14mm Riefler. I gather that's significant?
Jim
2008/8/25 Thomas A. Frank ka2cdk@cox.net
Jim;
Congratulations, that is a really nice looking clock!
You may have a real gem there. While the movement doesn't look like
anything special, the pendulum looks like a Riefler.
Which is something quite special...sort of like having a Thunderbolt
inside your bedside alarm clock...
Tom Frank
I will get that photo for you. (I didn't actually use a flash - that's just
the halogen floor light I use to see what I'm doing.) Also, being a keen
amateur photographer with some quite decent equipment I'll put some effort
in and make it a good one!
In that rack actually is a speaking clock (installed in Australia in the
1980s and my other prized possession) that I acquired a few years back along
with my recently purchased 5370B timer/counter and 3325B function generator.
Jim
Nice.
I'd love to have a photo of that with both the clock and the rack of HP
goodies both showing. Move to the right a little, maybe use a tripod and
turn
off the flash to get more uniform lighting and the result would be a
wonderful
contrast between old and new.
Folks,
I, too, had a great weekend.
The Thunderbolt arrived, plugged it in, and it promptly found it's self. I
can't wait to put it to work. Thanks to all (TAPR, time-nuts, etc.) for
their effort on my behalf.
My father (now deceased) collected and repaired clocks for 60 years leaving
my brother and I some unique pieces.
My prize is a 'FASHION' clock made by the Southern Calendar Clock Company,
St. Louis, Mo, patented March 18, 1879.
It is a two faced clock with two about ten inch diameter faces, one on top
and one on the bottom. The top face displays hours, minutes and seconds,
all with 'hands'. The bottom face displays the day of the month, 1 through
31, with a hand that points to the periphery and the month and day of the
week in two rectangular openings on either side of the center of the dial.
The unique feature is that it keeps long months, short months, and every 4
years, gives February 29 days. It is all mechanical, has two 'springs' for
power, one for time and the other to strike the hour of the day. It runs
for a week on a single 'wind' and keeps reasonable time. Not to 1 in 10E6
though.
Its shortcomings are leap seconds and Daylight Savings Time. Fully manual
on those I'm afraid.
It is completely mechanical with no electric parts. None the less, quite a
piece of work for the 1800's.
Thanks again to all for all the work that resulted in the Thunderbolt. I am
sure I will have questions in the future but none tonight.
Joe
-----Original Message-----
From: time-nuts-bounces@febo.com [mailto:time-nuts-bounces@febo.com] On
Behalf Of Jim Palfreyman
Sent: Monday, August 25, 2008 2:40 AM
To: Discussion of precise time and frequency measurement
Subject: [time-nuts] I now have a clock accurate to 10E-6!!!
Hi Folks,
Well I've had the best weekend since I've just acquired a pendulum clock
that used to be a telecommunication time standard in the 50s. It is a German
made Siemens pendulum master clock that is about 150cm high and has a
full-length seconds pendulum which is about a metre long. It is powered by
48V to automatically wind the weight up and will maintain time for about 8
hours without power.
The pendulum has an adjustment to raise and lower the 7.5kg weight to
calibrate the clock. One full turn of this knob will advance or retard the
clock by 40 seconds per day. It is graduated into 100 divisions enabling you
to adjust it within 0.4 seconds per day. Half way up the pendulum is a
little tray where you can deposit small weights for your final adjustment
(and most importantly without stopping the pendulum!)
Even though it's a master clock it is also designed to be synchronised to
another master clock and so there is an armature on the pendulum that can be
steered by a magnetic coil. I have no documentation on this bit, but when I
figure it out I naturally shall be driving it from a 1PPS reference. (See
photo.)
There are numerous contacts that are designed to open/shut at various times
including every second, every thirty seconds and minute. The photo shows the
mechanism behind the clock face.
By connecting the seconds contact up to my 5370B I tuned it quite quickly to
be accurate to about a second a day. Which is about 10 microseconds per
pendulum swing! I'm impressed a tick tock clock can do that. (Although it
pales into insignificance compared to what Harrison accomplished.)
It is beautifully constructed and now one of my prized possessions!
(I'll put some more photos in another post.)
Regards,
Jim
Well here's the photo I promised. I didn't take my time and I didn't use a
tripod. But you get the idea.
So on the left we have the Siemens Master Clock with the 14mm Riefler
pendulum. In the rack from the top we have:
-
5MHz OCXO backup for the speaking clock. This was used to hold the time
if the signal was lost from the central caesium master clock in Victoria.
It's a disciplined oscillator and was steered by a 1 KHz tone (based on the
caesium reference) down a phone line. -
Another 5MHz backup unit in case the first failed.
-
The main speaking clock unit. You can set the time, date, daylight
savings and leap seconds from here. -
A simple switch to control which speaking unit was "live".
-
The actual speaking unit. Converts time into voice and sends it back to
the main clock unit. Should be two of these, but I only have one. -
HP 5370B timer counter.
-
HP 3370B function generator.
-
Murray Greenman's GPS clock. It has a 10811 inside and provides the 1PPS
for the speaking clock. It also emulates the sound pips of VNG - the now
closed Australian short wave time service. At the press of a button it does
the announcements that used to happen every 15 minutes "This is VNG,
Lyndhurst, Victoria, Australia on 4.5, 7.5 and 12 MHz. VNG is a standard
frequency and time signal service of the Australian Telecommunications
Division". It does it all in the original voice that the older Australian
Ham Radio people know and love. That's because I have the original master
tape of that recording and I have digitised it. -
A lovely old HP nixie tube frequency counter. Still works as if it was
bought yesterday. Has a clever device on the right to read frequencies up
to 3GHz. All three of the HP counters and oscillators are of course fed off
a GPS based frequency reference (HP Z3815A hidden at the back of the rack). -
This is a part of the speaking clock that I don't use. It takes the time
from the main speaking clock unit (3) and creates pips (for example the six
pips per hour that was used on the radio stations) and then distributes it
down phone lines. -
This unit receives and decodes the master time signal from a
transmission unit that used to be in Victoria (connected to the caesium
clock). Since I don't have the transmission unit I cannot use this. I've
hot-wired the 1PPS directly into the speaking clock instead. -
No idea. Came in the rack. Something to do with two-tones. Not used and
doesn't power up.
To the top right of the rack is the rather nice "mesmeriser" clock kit from
Jaycar. It is, of course, sychronised. Below that is a three digit display
showing UTC milliseconds. The speaking clock has YY MM DD HH MM SS (in unit
5 in the rack) and so I thought milliseconds was just essential to complete
it.
To the right and slightly cropped is an old grandfather clock mechanism
which I'd hoped to steer via a 1PPS. However the pendulum swings at some
bizzare multiple of seconds so I gave up on it. Now I have my Siemens Master
Clock I don't care...
So there you go - I hope some of you find this post interesting!
Regards,
Jim
2008/8/26 Neon John jgd@johngsbbq.com
On Mon, 25 Aug 2008 17:40:14 +1000, "Jim Palfreyman" jim77742@gmail.com
wrote:
Hi Folks,
Well I've had the best weekend since I've just acquired a pendulum clock
that used to be a telecommunication time standard in the 50s.
Nice.
I'd love to have a photo of that with both the clock and the rack of HP
goodies both showing. Move to the right a little, maybe use a tripod and
turn
off the flash to get more uniform lighting and the result would be a
wonderful
contrast between old and new.
John
John De Armond
See my website for my current email address
http://www.neon-john.com
http://www.johndearmond.com <-- best little blog on the net!
Tellico Plains, Occupied TN
fas-cism (fash'iz'em) n. A system of government that exercises a
dictatorship of the extreme right, typically through the
merging of state and business leadership, together
with belligerent nationalism. -- The American Heritage Dictionary, 1983
time-nuts mailing list -- time-nuts@febo.com
To unsubscribe, go to
https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
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