[time-nuts] Re: Grandfather clock sync'd to 1PPS

[Andy Talbot]

>
> G3PLX did something similar, synchronising his GF clock to GPS.   But
> wanting to make no modifications to the pendulum, IIRC he placed a
> solenoid near the pendulum and used eddy current loss to slow it down.
>
> Andy
> www.g4jnt.com
>
>
>
>
> 
>  Virus-free.
> www.avg.com
> 
> <#m_7271374846254809346_DAB4FAD8-2DD7-40BB-A1B8-4E2AA1F9FDF2>
>
> On Thu, 11 Mar 2021 at 11:16, Peter Torry via time-nuts <
> time-nuts@lists.febo.com> wrote:
>
>> Hello Paul,
>>
>> You will still need to power the clock by winding it up when required.
>> The pendulum does not drive the clock, it regulates how the power is
>> allowed to escape from the driving force through a mechanism called the
>> escapement.
>>
>> As far as regulation goes the traditional was is to fis a soft Iron pole
>> piece to the pendulum about  a quarter of the way down from the
>> suspension and mount a coil of wire adjacent to this such that the pole
>> piece enters the coil on the excursion of the pendulum. The control
>> mechanism inserts a current through the coil in 100 micro amp steps to
>> bring the clock to time. The best way to monitor the timekeeping is by
>> using an optical detector and feeding the result back into the coil.
>>
>> There will still be variations from second to second because of
>> escapement error so it would be best to start with a clock using a dead
>> beat escapement or better.
>>
>> Enjoy the experiment.
>>
>> Regards
>>
>> Peter
>>
>>
>> On 11/03/2021 02:28, paul swed wrote:
>> > Like you all, I have always thought it would be fun to mess with a
>> > pendulum clock. Since I have one already what stands in the way? Well my
>> > Wife might think very differently about a few screws and wires in that
>> > clock. At the other end of the spectrum is Bill S. beautiful clocks he
>> has
>> > built. Not going to be anything like that. So will have to settle for a
>> > magical deal some day. Though for now Fleas and other gatherings are
>> out.
>> > I was wondering about winding the clock. And I see its still needed. I
>> had
>> > thought by driving the pendulum the clock would not need the drive
>> weight.
>> > Am I wrong about that? Or simply they are two different and separate
>> issues.
>> > Want to thank Gerald for sharing what he did and starting a great
>> thread.
>> >
>> > Regards
>> > Paul
>> > WB8TSL
>>
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>>
>
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[time-nuts] time-nuts list migration complete

[John Ackermann N8UR]

If you receive this message, that means the lists.febo.com mailing lists 
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[time-nuts] Re: Grandfather clock sync'd to 1PPS

[Tom Van Baak]

> One method of controlling a pendulum but allowing it to swing naturally

Morris,

Here are some examples from the web ...

"Build The Mystery Solar Powered Pendulum", by David Williams
http://nutsvolts.texterity.com/nutsvolts/201208/?folio=32#pg32

"Perpetual Swinging Pendulum", by Bill Bowden
http://www.bowdenshobbycircuits.info/swinger.htm

"Pendulum Driver", by Max Carter
http://maxmcarter.com/pendulum/index.php

"Electromagnetic Pendulum Drive Circuit", by Dick Bipes
https://carveshop.com/wp-content/uploads/2019/10/Electromagnetic-Pendulum-Drive-Circuit.pdf

"Regulated Electromagnetic Pendulum Drive", by Dick Bipes
https://carveshop.com/wp-content/uploads/2019/04/Regulated-Electromagnetic-Pendulum-Drive.pdf

You can also re-purpose commercial pendulum drive circuits. Search for 
words like "quartz movements with pendulums" or "clock pendulum drive" 
at clock suppliers like: www.timesavers.com, www.klockit.com, 
www.clockworks.com


If you're interested in pendulum clocks, there are several large 
organizations, magazines, web forums, and mailing lists. Contact me 
off-list.


/tvb


On 3/10/2021 9:51 PM, vilgot...@gmail.com wrote:

This has been a most interesting thread.

One method of controlling a pendulum but allowing it to swing naturally that
I am familiar with is to put a small unobtrusive magnet on the bottom of the
bob and an inductor on the base of the clock at the centre of the swing.
Depending on how you arrange the windings you can sense the period and
advance or retard the pendulum as required. It could be done very easily
with an Arduino or similar. It has the advantage that the pendulum can be
adjusted to keep as good time as possible and it will continue to do so if
the power fails.

And on the subject of remembering to wind the clock - the definitive
treatment of this subject is to be found in the opening chapter of "The Life
and Opinions of Tristram Shandy, Gentleman" first published by Laurence
Stern in 1759. I won't spoil the story by revealing the technique, but
suffice it to say that once read it's not easily forgotten!

Cheers,

Morris VK3DOC



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[time-nuts] Grandfather clock sync'd to 1PPS

[Peter Torry via time-nuts]

Hello Paul,

You will still need to power the clock by winding it up when required.  
The pendulum does not drive the clock, it regulates how the power is 
allowed to escape from the driving force through a mechanism called the 
escapement.


As far as regulation goes the traditional was is to fis a soft Iron pole 
piece to the pendulum about  a quarter of the way down from the 
suspension and mount a coil of wire adjacent to this such that the pole 
piece enters the coil on the excursion of the pendulum. The control 
mechanism inserts a current through the coil in 100 micro amp steps to 
bring the clock to time. The best way to monitor the timekeeping is by 
using an optical detector and feeding the result back into the coil.


There will still be variations from second to second because of 
escapement error so it would be best to start with a clock using a dead 
beat escapement or better.


Enjoy the experiment.

Regards

Peter


On 11/03/2021 02:28, paul swed wrote:

Like you all, I have always thought it would be fun to mess with a
pendulum clock. Since I have one already what stands in the way? Well my
Wife might think very differently about a few screws and wires in that
clock. At the other end of the spectrum is Bill S. beautiful clocks he has
built. Not going to be anything like that. So will have to settle for a
magical deal some day. Though for now Fleas and other gatherings are out.
I was wondering about winding the clock. And I see its still needed. I had
thought by driving the pendulum the clock would not need the drive weight.
Am I wrong about that? Or simply they are two different and separate issues.
Want to thank Gerald for sharing what he did and starting a great thread.

Regards
Paul
WB8TSL


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Re: [time-nuts] World's most precise.... wall clock

[Tom Van Baak]

> In tboltmon, the signal "strength" indications are displayed in units
> called 'AMU' for which I've been unable to find a definition.

Amplitude Measurement Units? There was a discussion about this some 
years ago. The TBolt (and other Trimble receivers) give a user the 
choice of reported GPS signal level in either AMU or dBc units. Mark 
Sims (Heather author) collected data using both units to create a 
cross-reference. I've attached his data (file: 
2010-Sims-TBolt-AMU-dBc.zip).


His reply from 2010 is here:

> From: "Mark Sims" 
> To: 
> Sent: Saturday, February 13, 2010 8:48 AM
> Subject: [time-nuts] Thunderbolt AMU to dBc conversion
>
> The data was collected in 0.1 dB / AMU steps. There was a lot of noise
> in the raw data (maybe ± 1 dB or AMU), but the general trend of the
> curve was quite distinct. I smoothed it out by hand and filled in a few
> (maybe 15) of the missing steps that had no signal.
>
> The 0.1 resolution of the raw data causes the piecewise linear steps in
> the data. I was going to run a smoothing filter over it, but the curve
> is pretty good as-is (especially considering how it was generated).
>
> Heather now uses a table lookup from 0.0 to 25.5 AMU with a linear
> approximation over 25.5 AMU to convert AMU values to dBc values when
> drawing the signal level map if the receiver is in AMU mode. The plots
> collected in AMU mode and dBc mode are virtually indistinguishable
> (within the normal variation seen between two different runs in dBc 
mode).


The entire thread is worth reading from the archives. [1] [2]

See also table 7.3 on page 124 of:

ftp://geodesy.noaa.gov/pub/abilich/papers/ABilichThesis.pdf

/tvb

[1] https://www.febo.com/pipermail/time-nuts/2010-February/044968.html

[2] 
http://lists.febo.com/pipermail/time-nuts_lists.febo.com/2010-February/027397.html


<>
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Re: [time-nuts] World's most precise.... wall clock

[Björn]

Sent from my iPhone

> On 10 Mar 2021, at 15:54, Dana 
> 
> I have convinced myself that the PPS output from my Tbolt is derived from
> the produced
> 10 MHz output, because if I trigger an o'scope from the PPS output, the 10
> MHz sinewave
> shows very little time jitter, perhaps 1 or 2 nsec.  So, I'm pretty happy
> with the T'bolt, with
> two (minor) exceptions:
> 
>> Its RF sensitivity seems rather poor compared to that of "modern"
> receivers (my unit
>was apparently made in the early 2000s).
> 
>> In tboltmon, the signal "strength" indications are displayed in units
> called 'AMU',
>for which I've been unable to find a definition.
> 
> Dana
>> 

Dana,

The Tbolt is different from most GPSDOs in that the 10MHz clocks the whole 
receiver. So there is no sawtooth error to correct for. Read the manual.

It is less sensitive, as was receivers from that manufacturer and age. Look in 
the manual what gain is expected at the antenna port.

AMU - “a mostly meaningless unit” is how I was described it from an industry 
insider. Note that you can change the unit to SNR if you want. Then SNR is also 
not always comparable  between manufacturers and models.

Kind regards,

  Björn 

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Re: [time-nuts] Grandfather clock sync'd to 1PPS

[vilgotch1]

This has been a most interesting thread.

One method of controlling a pendulum but allowing it to swing naturally that
I am familiar with is to put a small unobtrusive magnet on the bottom of the
bob and an inductor on the base of the clock at the centre of the swing.
Depending on how you arrange the windings you can sense the period and
advance or retard the pendulum as required. It could be done very easily
with an Arduino or similar. It has the advantage that the pendulum can be
adjusted to keep as good time as possible and it will continue to do so if
the power fails.

And on the subject of remembering to wind the clock - the definitive
treatment of this subject is to be found in the opening chapter of "The Life
and Opinions of Tristram Shandy, Gentleman" first published by Laurence
Stern in 1759. I won't spoil the story by revealing the technique, but
suffice it to say that once read it's not easily forgotten!

Cheers,

Morris VK3DOC



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