Re: [time-nuts] Need Time Help

[Peter Torry via time-nuts]

I must admit to being rather puzzled at the sub microsecond timing 
requirement as I use ntp to set the W7 clock in my computer and have not 
had any issues. In fact less than one second is OK for the usual two 
minute periods that are required to allow for the Faraday rotation. 
Although I use a GPSDO for a frequency reference I find JT software 
reasonably tolerant of frequency.  As I may be missing something I would 
welcome observations on how important the period timing requirement is, 
you never know I might get more contacts.


Regards

Peter


On 05/10/2016 12:50, Graham / KE9H wrote:

For the group. This ham is trying to work EME. Earth-Moon-Earth propagation
path. Aka, "moonbounce."

He is trying to time synchronize a system, where the other station he is
communicating
with can be any other place on the Earth that can also see the Moon.

So the system time sync is for a little bit tougher case than a local area
network.

--- Graham




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Re: [time-nuts] Visiting Greenwich

[Peter Torry via time-nuts]

Dave,

The rules have changed regarding photography for all National Trust 
properties so click away.


Regards

Peter


On 07/07/2016 21:41, Dave Martindale wrote:

Hmm.  When I was there yesterday I didn't see any "No Photography" signs,
so I photographed lots of the exhibits, including the four Harrisons . I
used flash, so I wasn't the least bit stealthy, and one of the staff was
only a few feet away.  Maybe they no longer care?

Dave

On Wednesday, 6 July 2016, Morris Odell  wrote:


  I can recommend the climb up the hill at Greenwich to anyone - it's
definitely worth the effort. They didn't allow photography of the Harrison
clocks but I did manage to sneak one or two before the minder got to me :-)

Morris
Melbourne, Australia



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Re: [time-nuts] Visiting Greenwich

[Peter Torry via time-nuts]

The original speaking clock ( in use from 1936 to 1963) has been 
restored to working order and is on show at the British Horological 
Institute at Upton Hall near Newark (UK). Speaking clock N0 2 that 
replaced No 1 is quartz controlled and also on view at Upton hall.  If 
anyone would like details of them just let me know.


Peter Torry



On 06/07/2016 06:20, Dave Brown wrote:
I have a pdf of a POEEJ article on the speaking clock that came into 
service 24 July 1936 if anyone is interested. I suspect this predates 
the one under discussion? I also have a two part article on the Mark 2 
built in the UK for Australia.(mid 1950s)

DaveB, NZ






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[time-nuts] Information request

[Peter Torry]

I have been given a 10MHz oscillator that appears to be in good physical 
condition but I have no further information on it hence this request.


It is marked as follows:-Quartzkeramic 2006/10SCD-531
10.000MHz   12v=
K 837383

Any information such as connection details, performance etc. will be 
greatly appreciated.

Regards
Peter
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Re: [time-nuts] Spectrum Analyzer Specifications

[Peter Torry]

Fellow Timenuts,

May I suggest the use of a software defined receiver (SDR) used with 
suitable attenuators on its antenna input.  I use a device called 
SDRPlay that is low cost, covers 100kHz to 2000MHz, and has a more 
sensitivity than most low cost Spectrum analysers.  Used with care the 
qualitative display is quite reasonable and compares well with my main 
analyser the only drawback being the  limited display width of 8MHz.  It 
would then leave more resources to purchase the important equipment.


Regards

Peter Torry

On 23/03/2016 14:04, jimlux wrote:

On 3/23/16 4:11 AM, Bob Camp wrote:

Hi

If you can see harmonics down to -60 dbc, that is about the most a 
normal spectrum
analyzer will do for you on a frequency standard. This *assumes* the 
part has a sine
wave output. Most standards are in the 10 MHz range, so an analyzer 
that will work to

= 40 MHz is probably a good idea.


Can you do this with a USB gizmo? Sure you can. Can you trust the 
results? That will
depend on the exact unit you get and your ability to calibrate it. 
Might it “only” be useful
to -50 dbc? Might it work to -100 dbc? That is part of the “did you 
pay $X or 10 times

that much question.






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Re: [time-nuts] Mechanical clock sound pickup circuit

[Peter Torry]

Andrea,

The watch or clock produces many sounds during its operation and the 
issue is selecting the required one.  As you wish to investigate the 
timing function may I suggest that you incorporate some form of level 
control to eliminate minor signals and allow only the strong sounds from 
the escapement.  You will find that even these will vary dependant upon 
the amount of drop each pallet has and if it is in beat.  It may be 
interesting for you to have a look at the various watch timing machines 
that are available and see if any ideas spring to mind.
I use a home-made system but various software and hardware solutions 
exist such as http://home.teleport.com/~gregsa/clocks/wtm/index.htm and 
http://www.delphelectronics.co.uk/products.html


Good luck with your experiments.

Peter



On 11/12/2015 18:44, Andrea Baldoni wrote:

Hello!

I decided to do some experiments with mechanical clocks, so I worked a little
on picking up escapement ticking sound, with the idea of processing it and
obtaining a "clean" digital pulse to feed a counter.

So far, I have not yet been able to find the best way to obtain a digital pulse,
but I have already built the preamp for the piezoelectrick pickup, that
I used to feed the mic input of a PC sound card for spectrum analysis.

The timing could eventually be done in software because the whole idea of
measuring watches by picking up their noise almost surely doesn't allow high
resolution anyway, but I will plan to try hardware solutions as well in the
future. I hope to be able to measure the jitter of the clock, but it will be
very hard.

In the meantime, with the free software Biburo you can download here

http://tokeiyade.michikusa.jp

you can regulate your wrist watch.

Best regards,
Andrea Baldoni


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[time-nuts] New GNSS receiver

[Peter Torry]

I thought the list may be interested in the following:

Lime Microsystems and Airbus Defence and Space, with funding from 
Innovate UK have announced a joint development of robust GNSS products. 
Airbus DS, using Lime’s Field Programmable RF (FPRF) transceiver 
technology, is developing a robust timing receiver that exploits signals 
from the new Galileo satellite navigation constellation.


See http://www.automotive-eetimes.com

Regards

Peter*
*
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Re: [time-nuts] NPR story on coupled pendulums

[Peter Torry]

Eric,

Yes, there is a benefit from using coupled pendulums.  As with any 
oscillator noise is the limiting factor and by using multiple pendulums 
the noise, mechanical disturbance, can be greatly reduced.  Two 
pendulums will suppress the x an y component and three pendulums will 
suppress the x, y ans z components.


There will be a consolidated response to the scientists enlightening 
them and showing the error of their ways.


Regards

Peter



On 30/07/2015 17:14, Eric Garner wrote:

Is there any stability benefit to having a bunch of coupled pendulum
clocks?

On Wed, Jul 29, 2015 at 4:22 PM, Bill Beam wb...@gci.net wrote:


These University Of Lisbon Scientists have rediscovered a very old wheel.

Old physics:  Two coupled nearly identical harmonic oscillators have two
stable states.
They will operate with relative phase = zero or 180deg. How they are
coupled is not
an issue; they only need to be able to transfer energy one to the other.




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Re: [time-nuts] Greek clocks - planets rather than seconds

[Peter Torry]

Hal,

Gear wheels have been cut by hand for many a century.  A simple dividing 
head made from wood and fixed to a mandrel would index a blank wheel and 
allow the teeth to be cut by a saw and then rounded up to a cycloidal 
shape with a file. As time progressed shaped files were used and later 
simple fly cutters with the cycloidal shape.


Files were made by hand in a similar way as that are made today. Once 
the correct material was chosen, originally iron and later steel, a 
blank was shaped and the teeth cut using a chisel. The file would then 
be hardened by heating and quenching followed by straightening and 
warping before it set.  As with most tasks machines either speed up the 
process or take the skill out of it. As an aside only use new files on 
brass until they have the edge taken off them then they can be used on 
harder materials.


There is somewhat more to the above but it would take up too much bandwidth.

Regards

Peter



On 11/05/2015 00:32, Hal Murray wrote:

Michael Wright talking about the Antikythera
   http://www.the-eg.com/videos/michael-wright-antikythera-resurrector-eg8

The video is 1/2 hour.  I thought it was good.  He's a colorful speaker.

Anybody know how they made gears back then?  Or machinery in general?  What
did they use for a file?  How did they make files?


The Computer History Museum is having an event:

May 13, 2015  10:30 AM
Secrets of the Antikythera Mechanism
   http://www.computerhistory.org/events/upcoming/

  In 1900, sponge divers off the coast of the tiny Greek island of Antikythera
made an astonishing discovery: the wreck of an ancient Roman ship lay 200
feet beneath the water, its dazzling cargo spread out over the ocean floor.
Among the life-size statues and amphorae was an encrusted piece of metal,
which after nearly a century of investigation, is finally revealing its
secrets




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Re: [time-nuts] New +/- 1 sec in 100 days mech clock

[Peter Torry]

You could always use the traditional method of piercing saw and files. 
Thinking about it I suppose files were the original milling machine.  Be 
aware that the horological approach is different from the engineering 
approach and there are numerous traps waiting for the unwary.  Harrison 
and Martin's clock B have remarkable performance but could still be 
improved by using multiple pendulums to overcome the noise effects for 
example a two pendulum clock is performing within 1 second in six months 
(so far) so I will have to get the hacksaw out for the three pendulum 
version - or is it back to the GPSDO.


Peter



On 20/04/2015 20:51, Attila Kinali wrote:

On Mon, 20 Apr 2015 09:59:06 +0200
Attila Kinali att...@kinali.ch wrote:


Mechanical, yes. Home brew, no. It is an absolutely stunning clock,
both in beauty and performance.

Given the fact that a CNC milling machine can be bought quite cheaply
today, i would say that homebrew is easily possible. All you need
is a good understanding on different materials and how to machine them.
(This can be aquired using various machining books out there)

Just to make sure there is no misunderstanding. What I ment here
was, that once you have the plans, machining the parts and building
the watch is easy. Comming up with a good plan is still hard.

Attila Kinali



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Re: [time-nuts] Looking for advice to get a submillisecond setup

[Peter Torry]

I am unsure which country you are in but the UK supplier 
http://www.galleon.eu.com/computer-time-clock.html has a range of 
reasonably priced units that may fit your requirements.


Regards

Peter Torry


On 20/02/2015 16:40, Chris Albertson wrote:

I think you're getting into receivers that are well into the hundreds of

dollars range, if bought new.

For an inexpensive NTP for few hundred dollars to get better than a
millisecond end of things, I think the integrated GPS antenna/receiver
with a suitable computer right next to it is the way to go.  Then you're
just running a network cable and power.


I paid $36 for two Motorola Oncore receivers.  These are 55 nanosecond (1
sigma) timing receivers.  I think today they cost about $25 each.  I paid
$27 for the timing antenna that is a helix the inside a pointed redone.
The dome has screw holes that fit a common galvanized pipe flange.  This is
not an expensive setup and the parts are all there on eBay.  You need to
add a power supply.  I use a plug-in power cube.

But as I said.  Use what you have all GPS receivers have more precision
than NTP can make use of.  You don't need high-end gear if the requirement
is only sub millisecond.

Mostly I'd say don't spend money on performance you don't need but in some
cases you get great performance for less money.


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Re: [time-nuts] MSF Scheduled Maintenance Periods

[Peter Torry]

Folkert,

As far as I know the transmitted signal has not changed and is its 
normal strength with me.  Have you thought that you may be experiencing 
some form of interference to the signal?  If you can monitor the signal 
on a receiver, maybe on a long wave broadcast receiver, you may find 
that there are many loud noises heard from wall mounted power units, 
computer supplies etc.  In particular the use of computer networking 
equipment that uses the household electricity supply cables, such as 
homeplug, can be very destructive.  Can you check if you have connected 
some new equipment such as a laptop, telephone charger etc and as a test 
disconnect them all and see if the receiver then works OK.


Best of luck in finding the problem

Peter


On 09/02/2015 12:12, folkert wrote:

MSF Scheduled Maintenance Periods

The MSF 60 kHz standard-frequency and time signal, broadcast by Babcock on
behalf of NPL, is occasionally taken off-air to allow maintenance work on
the masts and antennas at Anthorn Radio Station to be carried out in safety.
This means that your radio-controlled clock will not be picking up the MSF
signal, so may not be working correctly.

Could it be that they changed something with their setup?
A couple of years back I could receive MSF fine (Gouda, the
Netherlands) but this year (reconnected the radio in January) no bit
comes in at all. The led on the radio also flickers dramatically, not
once per second.


Folkert van Heusden



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Re: [time-nuts] MIT 2 inch cesium fountain, optically pumped

[Peter Torry]

Hi Bob,

Some time ago Hoptroff  produced a Cs pocket watch using the Symmetricom 
SA45s - now how long for a wrist watch !!


http://www.engadget.com/2013/05/01/hoptroff-no-10/

Peter
(still pendulum controlled)



On 20/11/2014 12:38, Bob Camp wrote:

Hi

So the wrist watch sized fountain that was promised 15 years ago isn’t gong to 
be here for Christmas this year?

Bob


On Nov 20, 2014, at 12:17 AM, Magnus Danielson mag...@rubidium.dyndns.org 
wrote:

Hi Rick,

They did not mention the complexity of the laser system they needed, especially 
considering that the optical bench of a fountain isn't all that small, and also 
because they want to de-tune lasers. While they seems to have an idea, they 
didn't touch on that subject.

Nice to see that people think in a different way thought.

Looking forward to see the progress on this one.

Cheers,
Magnus

On 11/20/2014 05:24 AM, Richard (Rick) Karlquist wrote:

See:

http://newsoffice.mit.edu/2014/portable-atomic-clocks-1112

Any comments?

Rick Karlquist N6RK
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