Re: [time-nuts] Anybody have suggestions for time related science fair projects?

[Philip Gladstone]

On 11/05/2018 07:23, jimlux wrote:

On 5/10/18 9:55 PM, Hal Murray wrote:


A few months ago, I was a judge for the county level middle school 
science

fair.  (I'm not very good at what they wanted, but that's a different
problem.)

What sort of interesting time related experiments can a middle school 
geek do?


Borrowing serious gear may not be off scale as long as a youngster 
can run it.




The whole area of celestial nav is time related and uses very simple 
equipment -


Telling time by measuring the sun in some way.  Occultation of stars 
by the moon.  Positions of jupiter's big 4 moons.


Pendulum experiments.  If the student has a way to change their 
altitude, can they measure changes in g.  Driving a pendulum.


Coupled resonators  (spring/mass, pendulum, vibrating rods)

Measuring the speed of light (Fizeau or Michelson method? Other ways)

Water clock, sand hour glass, etc.  Measuring performance variation 
over environmental variations.



the trick with good science projects is finding something that's not 
just a "lab demo" - where there's some engineering component to 
figuring out how to execute the demo with unusual or improvised 
equipment, or where you're measuring something that's not been done 
before.
The advice that we got when doing a middle school science project was 
that you wanted an experiment with only one variable (altitude or 
temperature etc) and a  measurement of a single variable (maybe over time).


Philip





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Re: [time-nuts] Designing an embedded precision GPS time server

[Philip Gladstone]

I built a couple of NTP time servers around this board: 
https://www.olimex.com/Products/ARM/ST/STM32-E407/open-source-hardware 
which supports IEEE1588. It also acts as a PTP source on the LAN. It is 
part of the IPv6 ntp pool and is currently serving about 1000 requests 
per minute. It uses a custom PCB to connect to a small display an the 
GPS board (it has support for a number of different GPS boards).


It just needs putting into a case to complete the project. Of course, 
the last 10% takes 90% of the time!


Philip


On 28/10/2017 15:58, Nick Sayer via time-nuts wrote:

That looks and sounds very, very much like what I want to do.

Thank you very much for your testing suggestions. When it comes time, I had 
indeed planned on adding it to the NTP pool if for no other reason than to 
contribute to the cause (but also for testing).

I believe I’m going to start with one of my GPS module breakouts and an E70 
XPlained development board. From a hardware perspective, I expect that to be 
reasonably close to what the final hardware will be (the one thing I would 
guess would change would be perhaps swapping out the PHY chip for one that’s 
capable of doing PHY level timestamping, if that’s necessary and possible).

But my plan at the moment is to first try to get something that even answers 
the phone, see how terrible it is, and then see what has to be done to make it 
truly worthy.

Those interested can follow the hackaday project. This whole thing is going to 
be open hardware and GPLed firmware (again, assuming I succeed).

https://hackaday.io/project/27873-embedded-gps-ntp-server


On Oct 27, 2017, at 12:27 PM, Leo Bodnar  wrote:

Hi Nick,

Last year I have designed an NTP server with sub-microsecond turnaround 
accuracy/jitter at fully saturated 100K+ packets/sec traffic (full 100Mb wire 
speed) that costs just £250 from stock.
Its holdover performance on signal loss is in the order of 4-5ms/day.
https://store.uputronics.com/index.php?route=product/product=60_70_id=92

If you can come up with a cheaper and higher performance alternative I am very 
interested in licensing your design.

When you come to testing I can highly recommend placing your prototypes in 
public NTP pool and asking the admins to add it to .ch zone - you are 
guaranteed to get full 110kpps traffic spikes that will help to flush out bugs.
Just a few devices collectively served 1.1 trillion packets in less than a year 
http://leobodnar.com/LeoNTP/ (and have been through the infamous snapchat 
incident.)

Jitter and holdover need to be tested on a controlled LAN segment - I can 
highly recommend contacting Denny Page on this list and sending him a unit to 
test.
He built sophisticated and highly tuned testing system that tracks timing 
jitter and offset down to dozens of nanoseconds accuracy.
Denny is vendor-neutral and provided honest and fair feedback while I was 
developing my unit.

Hope this helps!

Thanks
Leo

On 26 Oct 2017, at 17:00, time-nuts-requ...@febo.com wrote:


Date: Wed, 25 Oct 2017 17:53:46 -0700
From: Nick Sayer 

I’ve just completed a project (off topic) with the ATSAMS70 chip and learned a 
lot in a relatively short time, and I really like the result.

I am considering a new project based on its cousin, the ATSAME70. The E70 has 
an Ethernet 10/100 MAC built in as well as the rest of the stuff the S70 has 
(USARTs, SD/MMC, AES-256, TRNG, high-speed USB… it’s quite nice), and Atmel 
Start (the software development framework I’ve been using) purports to have a 
ready-to-use IP stack (alas, no IPv6, but it’s a starting point at least).

Where I am going with this is I am considering designing a precision embedded 
NTP/PTP server. I’d connect one of the SkyTraq modules I’ve got piles of up to 
a GPIO and USART and the Ethernet port would provide NTP/PTP. The idea behind 
making it an embedded system would be to try and make it as accurate as it 
reasonably can be with the hope that (at least on the local segment) it would 
wind up being more accurate than a Pi Zero doing the same thing. At the very 
least, you’d expect such a thing to be a whole lot less hassle to set up, given 
decent firmware.

This may be a fool’s errand, certainly, but looking at it from here, I would 
think that such a design might offer accuracy in the microsecond range, but 
that’s just a tremendously uninformed guess at this point (and what does that 
accuracy mean to a peer that might itself be incapable of better than 2 orders 
of magnitude coarser?).

Anybody have any ideas or suggestions along these lines?



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Re: [time-nuts] GPS plates shipped today

[Philip Gladstone]

I want to thank the both of you for putting this together.

Philip

p.s. I signed up with the USPS some time ago to get email whenever 
someone ships a package to me (https://my.usps.com/) and I just got the 
notification (with the tracking number).


On 25/05/2017 16:03, Jerry Hancock wrote:

Hello fellow curmudgeons,

Today I shipped the plates to the people that have paid both Steve and me.  For 
those that elected the flat rate shipping, they will arrive in a few days, 
maybe even Saturday, if not, Monday.  Those that elected the lower cost 
alternative should arrive no later than the end of next week, possibly a lot 
sooner.  I have tracking numbers for each parcel but don’t have the energy to 
type them into separate emails.  if on the outside chance your package doesn’t 
arrive by next Friday, please shoot me an email and I will track your package.

It’s been an interesting project and I learned a few things along the way that 
made it all worthwhile.

Thanks,

Jerry


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Re: [time-nuts] TAPR Oncore M12+ kit

[Philip Gladstone]

I was hoping that someone would design some end plates from PCBs -- it 
just needs the PCB design and then the production is easy. I've built 
cases before with PCBs as the front and rear panels -- they look nice.


I'm in for a group buy

Philip

On 28/04/2017 08:19, Stan wrote:

I would be interested in participating in a group buy for the end plates. I 
will need two of them.

Regards,
Stan
N6BYU

Date: Fri, 28 Apr 2017 09:56:55 +0100
From: Steve - Home 
To: Discussion of precise time and frequency measurement

Subject: Re: [time-nuts] TAPR Oncore M12+ kit
Message-ID: <802e38ff-adca-435f-866d-f821c6223...@cox.net>
Content-Type: text/plain;   charset=us-ascii

All,

To add to the excellent information Art has provided - I spoke with Candice 
Rincon at Phoenix Mecano and just received a quote from her for the end plates. 
There is a $100 minimum order policy at P-M, shipping and taxes additional. The 
end plates with gaskets and screws are $7.25 each so we'll need to order 14 end 
plates to meet the minimum; that's enough to do 7 enclosures. The plates are 
cast aluminum and are blank so you would need to drill your own holes per the 
diagrams Art provided.
I don't know how many GPS kits were sold but if there's enough interest maybe 
we can do a group order.

Steve
WB0DBS

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Re: [time-nuts] Time-nut going England!

[Philip Gladstone]

Yes -- Greenwich is a must. Also read up on why the GPS 0.0 E line 
is not on the mark that is etched in the ground. Then walk over to the 0 
point and admire your GPS receiver.


The Harrison clocks are a wonder to behold.

Philip

On 26/04/2017 11:46, Graham / KE9H wrote:

If you have never seen them, you must make a pilgrimage to see the Harrison
Clocks at the Greenwich Observatory.

If you have not read the book, you must read the book "Longitude" before
seeing the clocks.

--- Graham

On Wed, Apr 26, 2017 at 8:05 AM, Attila Kinali  wrote:


Hi

I'll be in the UK for three weeks and will have a "free" week
between 13th and 20th of May. I will most probably be around
the London area and maybe spend a day or two in Southampton.

If someone wants to meet for a beer or cup of hot chocolate,
or knows of time-nutty things to do, please let me know.

I would also appreciate if someone knows an affordable place
to stay at in London, so that it doesn't strain the purse
of this poor student too much.

 Attila Kinali




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Re: [time-nuts] Leap-second capture on laptop

[Philip Gladstone]

I added this message to the Linux kernel near the end of 1993. There is 
a companion message that indicates the removal of the leap second -- but 
this has never been seen (except in testing!).


In retrospect, it isn't clear that jumping the clock by a second was the 
right decision, but, at the time, it was the "obvious" thing to do.


Philip

On 31/12/2016 20:00, Magnus Danielson wrote:

Fellow time-nuts,

While not fancy by any means, my laptop captured the leap-second being 
inserted by this message in the /var/log/syslog:
Jan  1 00:59:59 greytop kernel: [78458.839942] Clock: inserting leap 
second 23:59:60 UTC




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Re: [time-nuts] Leap second on LEA-6T

[Philip Gladstone]

Bob,

I use the AID-HUI message to get the time of the next leapsecond. I use 
the utcWNF and utcDN to get the day number of the next leap second. 
Since it always happens at the end of the UTC day, this gives you the 
time. utcLS and utcLSF give you the the before/after offsets. Yes, it 
doesn't change often, but it doesn't need to.


Philip

On 31/12/2016 19:28, Bob Stewart wrote:

Here's the leap second as my GPSDOs saw it.  But, I'm still in the dark about 
how Ublox does their pending leap second notification.  There are very few 
messages that have any leap second info, and I had hoped that the aiding 
message AID-HUI would do something at the leap second.  But, the message 
doesn't seem to update more than once a day and there's no direct way to tell 
when the leap second will happen from the AID-HUI message that I can see.  So, 
does anyone have a good grasp on how to get the pending leap second info from a 
Ublox receiver?  I'm missing something that's probably intuitively obvious to 
everyone else.

20161231235959|P|250|500|000|3233|0539|3272|11|09|0.33|096.6| 
001.1|G-04.595|105.54|9681|7A236|07| 
50820161231235960|P|250|500|000|1063|0540|3271|11|09|0.33|010.2| 001.1|G 
09.106|105.54|967F|7A235|07| 507
2017010100|P|250|500|000|0642|0540|3271|11|09|0.33|001.9|-000.2|G 
02.113|105.54|9680|7A234|07| 507
2017010101|P|250|500|000|3230|0540|3271|11|09|0.33|096.4| 
000.2|G-03.822|105.54|9681|7A235|07| 508




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[time-nuts] My analog clock capturing the leap second

[Philip Gladstone]

https://goo.gl/photos/RZKqsgZqv2mH5UYK6

This is a video of my cheapo clock (which is NTP synchronized via an 
ESP8266 module running LUA). Actually synched to a local NTP/PTP server 
using GPS.


OT When the leap second happened, the kids complained that Netflix 
stopped working! Coincidence?


Philip

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Re: [time-nuts] A Leap Second is coming

[Philip Gladstone]

This is my clock (NTP synchronized) -- with a bit of luck, the second 
hand will stop (for a second) at the appropriate instant (7PM Eastern). 
I intend to catch it on video.


Unfortunately, this being an inexpensive clock, the plastic gears result 
in the hands not aligning quite correctly (it depends on the force of 
gravity). By the next leap second, I'll upgrade to a better clock.




Philip

On 30/12/2016 19:30, Azelio Boriani wrote:

The leap second warning is present in the PTB clock too (Europe):


On Fri, Dec 30, 2016 at 8:49 PM, Nick Sayer via time-nuts
  wrote:

I'm going to definitely observe my GPS clock to check its behavior. It *should* 
repeat second zero (in my case of 4PM PST). Not the most exactingly accurate 
depiction, but it's the best I can do with the architecture.

Sent from my iPhone


On Dec 29, 2016, at 12:22 AM, David J Taylor  
wrote:

Is everybody setup to watch it and collect lots of data?

Anybody have a list of tools/toys for collecting data?

An old favorite:
www.cl.cam.ac.uk/~mgk25/time/leap/test/timelog.c
=

Some tools here, to see which NTP servers are announcing the event:

http://www.satsignal.eu/software/net.htm#NTPLeapTrace

Perhaps they may be of use to someone?

Cheers,
David




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Re: [time-nuts] Ig Nobel ceremonies & time

[Philip Gladstone]

I was also there as the leader of an Official Delegation -- "Engineers 
for Accurate Time". Our performance when introduced was sub optimal 
(especially as seen in the Youtube video below). This is our delegation 
after the awards: https://www.flickr.com/photos/88087539@N00/29469880204/


As you can see, our time was maybe not quite as accurate as it could 
have been!


Philip


On 02/10/2016 21:51, Eric Scace wrote:

I had the happy fortune to attend this year’s Ig Nobel award ceremonies, the agenda 
of which is found here . This was the 26th 
First Annual Ig Novel Prize Ceremony

This year’s program featured “time”, including:
a mini-opera “The Last Second”, whose plot involves a leap second that goes 
very wrong.
micro-lectures by:
Prof Jenny Hoffman, Harvard physics: “What is a Leap Second, and Why Do We 
Create Them?”
John Lowe (NIST, Boulder): “How Scientists Decide When to Create a Leap Second, 
and How We Do It”
Eric Maskin, Nobel laureate, economics: “The Kinds of Financial Mischief That 
Could Be Done During an Unannounced Extra Leap Second”
Each time the word “time” was mentioned, the cheerleading section of the 
audience groaned.

All the micro-lectures were excellent — and John Lowe especially so. You can listen to it, 
the opera, and all the rest of the ceremony, on the upcoming Nov 25 “Science Friday” 
program on public radio. Broadcast times here . Or, if 
impatient, the entire ceremony is available on YouTube  
now.

I now return you back to our usual programming…



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Re: [time-nuts] Glass Envelope Quartz Crystals

[Philip Gladstone]

I dug around in my junk box, and found this:

https://plus.google.com/+PhilipGladstone/posts/JBNLMSq2rsE?pid=6247050011623528018=115465617973526125523

This is (according to the markings) a 71.137 kHz crystal made in 1948. I 
suspect that they just measured the crystal after manufacture rather 
than actually trying to make a 71137Hz crystal


After this discussion, I'm feeling the need to fire it up and see 
whether it still runs, and what the aging has done to the frequency


Philip

On 03/02/2016 07:11, Bob Camp wrote:

Hi

There is actually a range of crystals shown in the pictures. The gold plated 5 
MHz
crystal is probably an overtone part. It could be fairly precise. The 25 MHz 
part is
plated with something like silver. It probably is a *much* lower precision 
part. There
likely are long stories that explain just why this or that package got used in 
this
or that application.

Bob


On Feb 2, 2016, at 10:04 PM, Jeremy Nichols  wrote:

The OP's picture looks very much like the crystals that HP's "Frequency and 
Time" division in Santa Clara (02 was their division number) used to manufacture 
back in the 1970s. My picture shows a 1 MHz crystal that HP used in the predecessor to 
the HP-105A (perhaps the 101A).

Jeremy

http://s323.photobucket.com/user/Jeremy5848/media/Miscellaneous/Crystal_1140587_zps0jxjpoal.jpg.html



On 2/2/2016 12:24 PM, Don Latham wrote:

You have it right, iovane. At the least, they should be protected from light,
thermal radiation, and emf.   Won'drous things will happen if the crystal and
its structure are subjected to radiation through the glass. I'd suggest a foam
wrap in a tin can as a minimum. Put the oscillator cat in there too.
Don

iovane--- via time-nuts

I think that these crystals were designed to be placed in an oven, which
worked
as a shield too. I have a similar crystal made by Racal in the 60's, and in my
case it is fitted with the classic octal tube-type plug. It was housed (still
is) in a heavy massive shimmering chrome-plated cylindrical brass enclosure, a
beauty to see, It was the timebase of a tube-type synthesizer with lots of
tubes. Themperature control was achieved by means of a mercury thermometer in
which mercury actuated a contact when reaching a wire crossing the capillary
tube.

Antonio I8IOV


Da: Bob Camp 
Data: 02/02/2016 13.15
A: "Discussion of precise time and frequency measurement"
Ogg: Re: [time-nuts] Glass Envelope Quartz Crystals

Hi

Since the 25 MHz crystal has already been soldered into a circuit, putting it

in a

socket is probably not a real good idea. It’s also a leaded part. Even with

fat pins

sockets can be an issue. With wire leads, you are asking for trouble.

Functionally, there is little there is little difference between a glass

package crystal

and a metal package. About the only real one is the obvious - one has a metal

shield

you can (but sometimes don’t)  ground.

Bob



On Feb 1, 2016, at 9:58 PM, Daniel Watson  wrote:

Hi,

I purchased a pair of interesting glass envelope crystals for a project.
Here are some pictures:

http://syncchannel.blogspot.com/2016/02/glass-envelope-quartz-crystals.html

Does anyone have an idea about what mount/socket I should buy for these? I
read a previous thread on the list about Bliley crystals using a B7G mount,
but I'm not sure if that type might work here.

Also, when building up a circuit to make these oscillate, are there any
specific differences about crystals in this package that I should keep in
mind?


Thanks much,

Dan W.




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Re: [time-nuts] Glass Envelope Quartz Crystals

[Philip Gladstone]

Alan -- I should have checked Google. It turns out that 71.137 kHz was a 
Decca navigation frequency. Given that the network was being installed 
in the '40s, it seems to match up with the date on the crystal.


Philip

http://traktoria.org/files/radio/navigation/Radio_Navigation_Systems_for_Aviation_and_Maritime_use__AGARD-AG-63.pdf 
has all the details.


On 03/02/2016 12:30, Alan Melia wrote:

I think it was unlikely that that it was made "just to see where it would
come out" That is a flexural bar possibly an NT cut. 100KHz standards
were
commonly made in this format.
The British GPO had a factory at Mill Hill in N. London making these in
tube-like (valve in UK) enclosures, IO GT and B7G. I have a number of
unit
saved from the dumpster (skip in the UK).when the unit closed in the
early
60s. Remember there was a surge in telephones in this era and many of
these
frequencies were for FDM carriers on trunk sytems. This is
pre-synthersiser.

Also many special quality tubes were made for VHF in B7G with two or
three inch wires instead of pins to reduce the socket parasitics. so
these were probably still around in Russian factories to produce
components for the "Foxbat" etc.

Alan
G3NYK


- Original Message - From: "Philip Gladstone"
<pjsg-timen...@nospam.gladstonefamily.net>
To: <time-nuts@febo.com>
Sent: Wednesday, February 03, 2016 1:21 PM
Subject: Re: [time-nuts] Glass Envelope Quartz Crystals



I dug around in my junk box, and found this:

https://plus.google.com/+PhilipGladstone/posts/JBNLMSq2rsE?pid=6247050011623528018=115465617973526125523


This is (according to the markings) a 71.137 kHz crystal made in 1948. I
suspect that they just measured the crystal after manufacture rather
than
actually trying to make a 71137Hz crystal

After this discussion, I'm feeling the need to fire it up and see
whether
it still runs, and what the aging has done to the frequency

Philip

On 03/02/2016 07:11, Bob Camp wrote:

Hi

There is actually a range of crystals shown in the pictures. The gold
plated 5 MHz
crystal is probably an overtone part. It could be fairly precise.
The 25
MHz part is
plated with something like silver. It probably is a *much* lower
precision part. There
likely are long stories that explain just why this or that package got
used in this
or that application.

Bob


On Feb 2, 2016, at 10:04 PM, Jeremy Nichols <jn6...@gmail.com> wrote:

The OP's picture looks very much like the crystals that HP's
"Frequency
and Time" division in Santa Clara (02 was their division number)
used to
manufacture back in the 1970s. My picture shows a 1 MHz crystal
that HP
used in the predecessor to the HP-105A (perhaps the 101A).

Jeremy

http://s323.photobucket.com/user/Jeremy5848/media/Miscellaneous/Crystal_1140587_zps0jxjpoal.jpg.html




On 2/2/2016 12:24 PM, Don Latham wrote:

You have it right, iovane. At the least, they should be protected
from
light,
thermal radiation, and emf.   Won'drous things will happen if the
crystal and
its structure are subjected to radiation through the glass. I'd
suggest
a foam
wrap in a tin can as a minimum. Put the oscillator cat in there too.
Don

iovane--- via time-nuts

I think that these crystals were designed to be placed in an oven,
which
worked
as a shield too. I have a similar crystal made by Racal in the 60's,
and in my
case it is fitted with the classic octal tube-type plug. It was
housed
(still
is) in a heavy massive shimmering chrome-plated cylindrical brass
enclosure, a
beauty to see, It was the timebase of a tube-type synthesizer with
lots of
tubes. Themperature control was achieved by means of a mercury
thermometer in
which mercury actuated a contact when reaching a wire crossing the
capillary
tube.

Antonio I8IOV


Da: Bob Camp <kb...@n1k.org>
Data: 02/02/2016 13.15
A: "Discussion of precise time and frequency
measurement"<time-nuts@febo.com>
Ogg: Re: [time-nuts] Glass Envelope Quartz Crystals

Hi

Since the 25 MHz crystal has already been soldered into a circuit,
putting it

in a

socket is probably not a real good idea. It’s also a leaded part.
Even with

fat pins

sockets can be an issue. With wire leads, you are asking for
trouble.

Functionally, there is little there is little difference between a
glass

package crystal

and a metal package. About the only real one is the obvious -
one has
a metal

shield

you can (but sometimes don’t) ground.

Bob



On Feb 1, 2016, at 9:58 PM, Daniel Watson
<watsondani...@gmail.com>
wrote:

Hi,

I purchased a pair of interesting glass envelope crystals for a
project.
Here are some pictures:

http://syncchannel.blogspot.com/2016/02/glass-envelope-quartz-crystals.html


Does anyone have an idea about what mount/socket I should buy for
these? I
read a previous thread on the list about Bliley crystals using
a B7G
mount,
but I'm not sure if that type might work here.

Also, when building up a circuit to make these oscillate, are
th

Re: [time-nuts] Modern HW replacement for ATOM based NTP server?

[Philip Gladstone]

On 4/8/15 17:13, Attila Kinali wrote:
The Cubie borads and the stuff done by Olimex would be also quite 
good. Especially Olimex is known for their very good user support, as 
they specifically sell to tinkerers and engineering companies. This 
also includes that their boards have almost all I/O pins available on 
connectors.
My NTP servers are based around Olimex boards running an RTOS with a 
custom NTP server (and a PTP client/server as well). Mostly put together 
for fun. Just left to mount into a case and put some polish on the 
display...


Philip

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[time-nuts] Frequency doubler 5/10 and distribution amplifier for Lucent KS-24361

[Philip Gladstone]

I'm coming late to this thread from January -- but did anybody ever make 
the PCBs for Gerhard's 10MHz output board? I'm interested.


I just got my pair of RFTG's.

Philip
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Re: [time-nuts] Recording mains frequency/phase [WAS: No GPS satellites]

[Philip Gladstone]

On 2/26/15 20:39, Charles Steinmetz wrote:

ben wrote:


I'm going to have to build one of these. Assume you have some sort of
circuit that converts low-voltage AC from a transformer secondary to
a pulse train, start a timer, and count x amount of pulses?


Here is a zero-cross detector designed for this purpose:

http://www.ko4bb.com/manuals/download.php?file=02_GPS_Timing/Simple_AC_Mains_Zero_Crossing_Detector.pdf


Most mains-nuts feed the ZCD pulse to the DCD line of a PC's RS232
port and use the computer to time-stamp the crossings and append them
to a file of such time stamps.
If we all did this, then I realize that we could identify the different 
power grids. However, I wonder if there is any interesting variation 
*within* a grid. As the electricity flows vary throughout the day, it 
seems possible that the phase difference between two people on the same 
grid would actually change (a bit).


Has anybody done this experiment?

Philip
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