Re: [time-nuts] Casio Wave Ceptor wrist watch - quick accuracy test

[Jim Palfreyman]

I posted about my G-shock watch on this forum probably about 10 years ago.
Go look them up. I found mine superbly accurate and being in Tasmania I
cannot connect to any LF service. After a while it started to get a little
worse and I found you can take the back off and calibrate it.

My rechargeable battery has just started to fail and so I've ordered a new
one.

Jim


On Mon, 11 Jun 2018 at 18:20, Esa Heikkinen  wrote:

> Hi!
>
> There seems to be some kind of comeback going on with 80's style digital
>   watches. You may find replicas of some 80's models or even re-makes of
> the original models from original manufacturer.
>
> So I decided to get one. As a time-nut my primary goal was to have radio
> controlled 'atomic' model. So I ended up to Casio Wave Ceptor
> WV-59DE-1AVEF. There's many models available from basic digital models
> like this to very nice ones with with full titanium body (analog style).
> But because of the 80's is hot it had to be digital...
>
> Wave Ceptors suport all time signals formats (US, UK/German and Japan)
> and correct standard is automatically selected when home city is set.
>
> One of the first things to do was to test the accuracy with radio
> syncronization turned off. Correct time was fist set with DCF77. Then I
> switched off the synconization. After beign about three days off there
> was no significiant visible error on time. In the video we can see
> however about one frame error, which means about 40 milliseconds. Still
> that's pretty good result for wrist watch. Also, the syncronization will
> occur once per day when the reception is good.
>
> So the watch must be at least calibrated in the factory. Don't know if
> the watch performs any kind of self-calibration according to radio
> syncronization results, most likely not - but it would be technically
> possible.
>
> So far so good, it's accurate enough - at least as new. When
> syncronization is turned on, there should never be visible error on time.
>
> Here's my test video:
> https://www.youtube.com/watch?v=_A23buFeHd0
>
> --
> 73s!
> Esa
> OH4KJU
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Re: [time-nuts] How good is your ADEV at 10E7 seconds? :)

[Jim Palfreyman]

Approximately 6% of pulsars "glitch" and yes these (typically young)
pulsars are poor time standards. The glitching is most likely caused by
unpinning of vortices in the superfluid outer core. This causes a momentum
transfer from the core to the crust - and a speed-up. The Vela pulsar (freq
of ~11 Hz) is the most famous of the glitching pulsars as it glitches
regularly (approximately every three years). The last glitch of Vela (Dec
2016) had a deltaF/F of about 1.4E-6.

However millisecond pulsars are completely different. They spin at hundreds
of Hz, typically don't glitch, and PSR J0437-4715 will give many atomic
clocks a run for their money. It has an error in its period (5.75 ms) of
9.9E-17 and an error in its period derivative of 9E-26. The idea was to
monitor an array of millisecond pulsars and use this to detect
gravitational waves. For many years it was a race between LIGO and the
pulsar array to find GW. LIGO won.

Incidentally, LIGO has looked for GW coming from a pulsar. Vela was chosen
as its frequency is in the LIGO sweet spot. Nothing was found however (
https://arxiv.org/pdf/1104.2712.pdf) - but this was 7 years ago.


Jim





On 18 November 2017 at 13:24, Bob kb8tq  wrote:

> Hi
>
> There are a number of papers on pulsars as time standards. The gotcha
> in the observed data (that has been measured over long time periods) has
> been random frequency jumps. Put another way, 10 million seconds and
> beyond *is* the problem. It’s going to take a *lot* of monitoring for a
> very long
> time to convince people that a specific pulsar is a good idea.
>
> Bob
>
> > On Nov 17, 2017, at 8:54 PM, Hal Murray  wrote:
> >
> >
> > Context is the what-next portion of a recent LIGO talk.  For those of you
> > that missed it (or didn't pay enough attention), on Aug 17th, they got
> good
> > data from a pair of neutron stars.  1.7 seconds later, the Fermi
> satellite
> > got a gamma ray burst.  Within a day, the optical guys had found a new
> spot.
> > Over the next days and weeks, they got data over the whole spectrum,
> radio to
> > X-rays.  (There were 70 observatories lined up to pounce.  Everybody
> wanted
> > in on the action.)
> >
> > LIGO only works for roughly the audio spectrum.  At the low and high
> ends,
> > the noise goes up.  Lots of people are working on how to build gear that
> will
> > work at other wavelengths.
> >
> > One proposal is to monitor pulsars.  There might be stuff leftover from
> the
> > big bang with a period of a year or so.  If you can get good timing from
> a
> > pulsar, you might be able to see it.  I suspect that will take "good"
> timing
> > to a scale that would astonish most time-nuts.
> >
> >
> >
> > --
> > These are my opinions.  I hate spam.
> >
> >
> >
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[time-nuts] Tsunami detection via GPS

[Jim Palfreyman]

Some here may find this of interest.

http://www2.unb.ca/gge/Resources/gpsworld.february08.pdf


Jim Palfreyman
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Re: [time-nuts] Next Aug 21 eclipse and time flow

[Jim Palfreyman]

Personally I go with the Nature article. The other papers look like they
are anomaly hunting because they have a known event.

Having said that, we have two H masers at our observatory in Hobart and we
have a system set up to measure their phase difference down to about 0.03
ns. I will report back any anomaly.

We, of course, are not in the path of the eclipse, however gravitationally
there is still an alignment. Just through the Earth.


Jim Palfreyman


On 29 May 2017 at 08:17, iovane--- via time-nuts <time-nuts@febo.com> wrote:

> On august 21 2017 a solar eclipse will sweep USA from coast to coast. A
> lifetime opportunity to do coordinated experiments to check this or that.
> One of the questions that doesn't have a final answer yet is whether or not
> solar eclipses could affect the flow of time. They exist conflicting
> reports: Negative: http://www.nature.com/nature/journal/v402/n6763/full/
> 402749a0.html Positive: http://home.t01.itscom.net/
> allais/blackprior/zhou/zhou-1.pdf  http://home.t01.itscom.net/
> allais/blackprior/zhou/zhou-2.pdfPersonally I believe that the positive
> results were due to spurious responses of the atomic clocks to something
> else than gravity, or the clocks failed for some reason (e.g. jumping
> crystals then steered), or lower quality clocks had been sold to China.
> Anyway the recorded data do show an anomaly.As far as I know, no atomic
> clock tests are planned anywhere for that circumstance, but sincerely I
> don't believe this is the truth.Maybe the US time-nuts community, using its
> plenty
>  of atomic clocks, could give the final answer doing tests during the
> above mentioned eclipse.US time-nuts, what about the idea of doing
> yourselves a large scale coordinated test? Or do you actually believe that
> this question is already definitively closed?(Even discovering that atomic
> clocks might respond to someting else than gravity would be of great
> interest).Antonio I8IOV
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Re: [time-nuts] calculating stats with gaps in the data

[Jim Palfreyman]

If you do want to Fourier transform your data and you *do* have missing
data points, I can highly recommend the Lomb-Scargle periodogram. I put it
through its paces a while back. I took 3 sin waves of different periods and
amplitude of 1 and added them together. I used 1 data points. Then I
added Gaussian noise of various standard deviations. And I also removed
various amounts of data up to 90%.

The LSP still found the periods with noise of sd=5 and 90% of the data
gone. With sd=10 it could still find signal with 50% of the points removed.

I have some nice plots of all this if anyone is interested.

The main disadvantage of LSP is speed. It performs as O(n^2). This was a
huge disadvantage back in the 70s when it was published, but with today's
computing power it's not a problem. Unless you have 100 data points,
then patience is required.

Jim Palfreyman


On 26 May 2017 at 07:12, Michael Wouters <michaeljwout...@gmail.com> wrote:

> There are 'better' ways of handling gaps when calculating ADEV and
> siblings. Patrizia Tavela has a nice method: you pad out the time series,
> tagging missing points with NaNs say, and then if a difference contains a
> missing data point, you drop it. It works very well. I expect this is in
> Stable32. I think it's implemented in allantools. It's definitely
> implemented in the Matlab functions I wrote (tftools on GitHub).
>
> Cheers
> Michael
>
> On Fri, 26 May 2017 at 12:00 am, Tom Van Baak <t...@leapsecond.com> wrote:
>
> > Only Stable32 handles data gaps seamlessly. Give it a try (read the
> manual
> > for details).
> >
> > But also ask yourself how much gaps matter. Yes, they affect the accuracy
> > of your y-axis sigma scale and your x-axis tau scale. A few seconds every
> > 30 minutes is, what, a 0.1% error? That's like one pixel in a ADEV plot;
> > not significant.
> >
> > What I've done when I need a perfectly seamless data set is just
> > interpolate for rare and obviously missing phase data points. That keeps
> > the timescale intact. This is especially important if you plan to Fourier
> > transform the data: under no circumstances do you want to slip a sample
> in
> > that case.
> >
> > /tvb
> >
> > - Original Message -
> > From: "jimlux" <jim...@earthlink.net>
> > To: "Discussion of precise time and frequency measurement" <
> > time-nuts@febo.com>
> > Sent: Thursday, May 25, 2017 6:11 AM
> > Subject: [time-nuts] calculating stats with gaps in the data
> >
> >
> > > I'm looking at the python AllanTools package.. does it deal with gaps
> in
> > > the data series (e.g. I've got a series of phase and/or frequency
> > > measurements, 1 per second, but there's gaps of a few seconds every 30
> > > minutes or so)
> >
> > ___
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[time-nuts] Name of integral of timing residual

[Jim Palfreyman]

Folks,

I'm after the formal name of something (if it exists), and this group, if
any, should know.

Consider a plot of a timing residual vs time. Say a watch against a maser,
residual=watch-maser.

Now if I now plot the cumulative sum (think integral) of the residual,
that's going to give me an overall view of how the clock is performing over
time. (If it helps, think of PID controllers and how they work in the "I"
part.)

Now if you look at *motion* of an object over time, and you integrate its
acceleration you get velocity, integrate again you get displacement.
Integrate again and you get "absement" and again you get "abcity" (I only
recently discovered these terms).

Does the integral of a timing residual have a name, and does the integral
of *that* have a name as well?

Any thoughts?


Jim Palfreyman
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Re: [time-nuts] How good is the left end of your ADEV curve?

[Jim Palfreyman]

I can't recall what I said before, but it *has* been done in the backyard
before. There's good news and bad news. The good news is that all the
software for processing your data: coherent dedispersion, folding, moving
all arrival times to the solar system barycentre, Einstein delay, Shapiro
delay, fitting, analysis etc is open source. You need DSPSR, PSRCHIVE, and
TEMPO2 and a unix machine to run them on.

The bad news:

Vela had a declination of -45 10 35 which means it's not visible very often
for you northerners. The second brightest pulsar has a similar declination.
After that, forget it - they are too faint.

Observing of individual pulses requires around a 20+ m radio telescope with
a receiver cooled to 20K (at ~1400 MHz). However using the above software
you can fold your data on the latest pulse period (which I can provide if
needed) and this then brings things down to a possible level:

You'll need a dish that can track. One that is 2 m across might just work.
Frequency choice is important. The lower the frequency the stronger the
pulse, but also multipath scattering smears the pulse out. Around 1400 MHz
is a good choice for removing the scattering, but may be too faint for
small dishes. If you went with ~600 MHz that could work - but do check any
local RFI.

If you didn't track, but just waited for the pulsar to pass through the
beam, you'd get about 2 minutes of data. That *might* be enough to fold and
get a signal.

It'd be a long, but awesome, project to work on.

The really cool part is that Vela glitches (speeds up) in rotation ~3 years
by around deltaf/f =10^-6 and you could measure that. It just glitched in
December (and I was observing at the time!), so you have another 3 years to
get building.

As to timing, any half decent GPSDO would be fine.

Oh, almost forgot, you'd also need a sampler.


Jim Palfreyman



On 26 January 2017 at 13:58, Tom Van Baak <t...@leapsecond.com> wrote:

> > What can I do at home, to observe such processes? Or is it way beyond
> > any imagination to participate in any such experiments?
> >
> > Volker
>
> LIGO is a billion dollar experiment, involving thousands of PhD's so it
> will be some time until you can do that sort of stuff alone at home, or
> with your family.
>
> Jim Palfreyman has mentioned before what it would take to do Pulsar
> measurements as a home experiment. Search for the old threads or he can
> jump in to remind us why it can't or hasn't been done yet. See also the
> thread a month ago about a DIY H-masers since you'll want some of them on
> hand before you start.
>
> It's worth spending time reading anything about LIGO. The experiment is
> out-of-this-world clever, complex, sensitive. And it actually works! Unlike
> the particle physics tree, which seems to be nearing the end of bearing
> fruit, LIGO is at the very beginning of an entirely new way to study the
> universe.
>
> /tvb
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Re: [time-nuts] How good is the left end of your ADEV curve?

[Jim Palfreyman]

First, a picky - but important - point. There is a difference between
"gravity waves" and "gravitational waves". When you go to the beach and
watch the waves crash on the shore, that's an example of a gravity wave.

Now, onto the far more interesting topic of gravitational waves and my pet
topic, pulsars.

Pulsars most likely give off gravitational waves. The rotate at a rate
anywhere from 1/12 Hz to 716 Hz. The brightest (in a radio sense) and one
of the closest pulsars is the Vela pulsar which rotates at 11.18677266 Hz
(as of a few days back). This frequency is in the sensitivity bands of
Advanced LIGO and Advanced VIRGO, but the gravitational waves from Vela are
probably too "faint" to be detected. But there is still no harm in trying.


Jim Palfreyman



On 25 January 2017 at 16:15, Hal Murray <hmur...@megapathdsl.net> wrote:

> way way way left.
>
> Ray Weiss was the speaker at the Stanford Physics Colloquium today.  In
> case
> you don't recognize the name, he is one of the leaders of the LIGO project
> that detected gravity waves about a year ago.
>
> He's a good speaker with a neat topic.  He spent a lot of time giving
> credit
> to other people.
>
> One of the far-out future ideas he mentioned was collecting data on lots of
> pulsars.  If you could get good enough data, maybe you could see gravity
> waves wandering around the universe.  (Maybe leftover from the big bang.  I
> didn't catch that part.)
>
> The time scale is months or years.  Micro Hertz.  The unit for wavelength
> would be light-years.
>
> How long will it be before we need a gravity-nuts list?
>
> --
> These are my opinions.  I hate spam.
>
>
>
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Re: [time-nuts] Measuring sidereal/solar time? Re: A Leap Second is coming

[Jim Palfreyman]

I don't think we could call it "amateur/semi-pro" but the millisecond
pulsar J0437-4715 would be perfect for this. Bright and precise.

Only for southern hemisphere people though.

:-)


Jim Palfreyman


On 30 December 2016 at 19:59, Anders Wallin <anders.e.e.wal...@gmail.com>
wrote:

> out of curiosity, are there any amateur/semi-pro experiments that can
> measure the length of the solar or sidereal day to sub-millisecond
> resolution?
> To reproduce data like this:
> https://upload.wikimedia.org/wikipedia/commons/5/5b/
> Deviation_of_day_length_from_SI_day.svg
>
> Something in the sky that goes "ping" every day - detected with a pointing
> accuracy of < 1ms/24h or <0.01 arc-seconds (!?). Or perhaps two
> satellite-dishes pointed at the sun and noise-correlation/interferometry??
>
> Anders
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[time-nuts] Sapphire oscillators

[Jim Palfreyman]

Anyone got any comments on this?

http://www.theleadsouthaustralia.com.au/industries/technology/worlds-most-precise-clock-set-for-commercial-countdown/


Jim Palfreyman
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[time-nuts] Atomic Watch

[Jim Palfreyman]

Well I think there's a mistake or two here...

https://www.inverse.com/article/20497-john-patterson-atomic-ce
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Re: [time-nuts] Caroliine .. I need to move on

[Jim Palfreyman]

Well I'm intrigued!


On 2 October 2016 at 15:53, Ian Stirling  wrote:

> going to the emergency place
> ___
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Re: [time-nuts] Q/noise of Earth as an oscillator

[Jim Palfreyman]

Hi Tom,

You said: "you need energy; you need energy loss; you need cycles over
which that loss repeatedly occurs."

With regard to the earth, where is the first one? Sure it was there at the
start when the solar system formed, but where is it now?

Jim


On 1 August 2016 at 12:16, Tom Van Baak  wrote:

> Hal:
> > Is there a term other than Q that is used to describe the rate of energy
> loss
> > for things that aren't oscillators?
>
> Jim:
> > cooling (as in hot things)
> > discharge (as in capacitors and batteries)
> > leakage (as in pressure vessels)
> > loss
>
> Scott:
> > An irreversible process would be a better description versus energy loss.
> > Like joule heating (resistance, friction).
>
> Notice that these are all energy losses over time; gradual processes with
> perhaps an exponential time constant, but without cycles or periods. We
> know not to apply Q in these scenarios.
>
> But when you have an oscillator, or a resonator, or (as I suggest) a
> "rotator", it seems to make sense to use Q to describe the normalized rate
> of decay. So three keys to Q: you need energy; you need energy loss; you
> need cycles over which that loss repeatedly occurs.
>
> We use units of time (for example, SI seconds) when we describe a rate.
> But here's why Q is unitless -- you normalize the energy (using E / dE)
> *and* you also normalize the time (by cycle). No Joules. No seconds. So
> having period is fundamental to Q. It's this unitless character of Q (in
> both energy and time) that makes it portable from one branch of science to
> another. And if you measure in radians you can even get rid of the 2*pi
> factor ;-)
>
> Without controversy, lots of articles define Q as 2*pi times {total
> energy} / {energy lost per cycle}. To me, a slowly decaying spinning Earth
> meets the three criteria. It appears to follow both the letter and the
> spirit of Q.
>
> Bob:
> > ummm…. Q is the general term of rate of energy loss and we just happen
> to apply
> > it to oscillators in a very elegant fashion….
>
> Oh, no. Now we have both quality factor and elegance factor!
>
> /tvb
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Re: [time-nuts] Q/noise of Earth as an oscillator

[Jim Palfreyman]

> What about an ADEV/TDEV plot of the pulsar J0437-4715?

Very boring. It's a straight line from top left to bottom right. :-)

See page 5 of this: http://arxiv.org/pdf/1004.0115.pdf

Jim Palfreyman


On 29 July 2016 at 17:33, Azelio Boriani <azelio.bori...@gmail.com> wrote:

> What about an ADEV/TDEV plot of the pulsar J0437-4715?
>
> On Fri, Jul 29, 2016 at 12:39 AM, Jim Palfreyman <jim77...@gmail.com>
> wrote:
> > Hi All,
> >
> > Tom gave me a nudge to look here - I hadn't been following this thread.
> >
> > For those that don't know, I study pulsars and so the way we measure what
> > pulsars do could be relevant to this discussion.
> >
> > First, I have never heard of a Q measure when referencing a pulsar. I
> think
> > the key here is that it's not resonating as such. Rotating yes,
> resonating
> > no.
> >
> > Pulsars spin and slow down due to giving off energy (magnetic dipole
> > radiation). So in the pulsar world we mainly refer to spin frequency (F0)
> > and frequency derivative (F1). With some of the younger and more
> "erratic"
> > pulsars, F2 (and further) can be modelled.
> >
> > Here's some data on the Vela pulsar (hot off the presses - measured just
> > now):
> >
> > F0  11.1867488542579
> > F1  -1.55859177352837e-11
> > F2  1.23776878287221e-21
> >
> > Vela is young and erratic. Millisecond pulsars are outstanding clocks.
> > Here's the data for J0437-4715 - one of the most stable pulsars we know
> > about:
> >
> > F0  173.6879458121843
> > F1  -1.728361E-15
> >
> > I'm sure the "Q" of Vela would be pretty decent - but I can tell you now,
> > as a time-keeper, she's useless.
> >
> >
> > Jim Palfreyman
> >
> >
> >
> > On 28 July 2016 at 20:50, Tony Finch <d...@dotat.at> wrote:
> >
> >> Neville Michie <namic...@gmail.com> wrote:
> >>
> >> > The conical pendulum has a simple form of a weight on a string,
> instead
> >> > of oscillating in one plane as a conventional pendulum, it swings
> around
> >> > in a circular orbit in the horizontal plane. It has a definite
> resonant
> >> > frequency.
> >>
> >> I don't think it does have a resonant frequency, any more than the Earth
> >> does: the angular velocity of the pendulum is sqrt(g/h) where h is the
> >> height of the pendulum; give it more energy, it swings higher, so h is
> >> smaller, so the frequency is higher.
> >>
> >> Tony.
> >> --
> >> f.anthony.n.finch  <d...@dotat.at>  http://dotat.at/  -  I xn--zr8h
> >> punycode
> >> South Thames, Dover: Southwesterly 5 or 6. Slight or moderate. Rain or
> >> showers. Good, occasionally poor.
> >> ___
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> >> and follow the instructions there.
> >>
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Re: [time-nuts] Q/noise of Earth as an oscillator

[Jim Palfreyman]

Hi All,

Tom gave me a nudge to look here - I hadn't been following this thread.

For those that don't know, I study pulsars and so the way we measure what
pulsars do could be relevant to this discussion.

First, I have never heard of a Q measure when referencing a pulsar. I think
the key here is that it's not resonating as such. Rotating yes, resonating
no.

Pulsars spin and slow down due to giving off energy (magnetic dipole
radiation). So in the pulsar world we mainly refer to spin frequency (F0)
and frequency derivative (F1). With some of the younger and more "erratic"
pulsars, F2 (and further) can be modelled.

Here's some data on the Vela pulsar (hot off the presses - measured just
now):

F0  11.1867488542579
F1  -1.55859177352837e-11
F2  1.23776878287221e-21

Vela is young and erratic. Millisecond pulsars are outstanding clocks.
Here's the data for J0437-4715 - one of the most stable pulsars we know
about:

F0  173.6879458121843
F1  -1.728361E-15

I'm sure the "Q" of Vela would be pretty decent - but I can tell you now,
as a time-keeper, she's useless.


Jim Palfreyman



On 28 July 2016 at 20:50, Tony Finch <d...@dotat.at> wrote:

> Neville Michie <namic...@gmail.com> wrote:
>
> > The conical pendulum has a simple form of a weight on a string, instead
> > of oscillating in one plane as a conventional pendulum, it swings around
> > in a circular orbit in the horizontal plane. It has a definite resonant
> > frequency.
>
> I don't think it does have a resonant frequency, any more than the Earth
> does: the angular velocity of the pendulum is sqrt(g/h) where h is the
> height of the pendulum; give it more energy, it swings higher, so h is
> smaller, so the frequency is higher.
>
> Tony.
> --
> f.anthony.n.finch  <d...@dotat.at>  http://dotat.at/  -  I xn--zr8h
> punycode
> South Thames, Dover: Southwesterly 5 or 6. Slight or moderate. Rain or
> showers. Good, occasionally poor.
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Re: [time-nuts] LSEM (Leap Second Every Month)

[Jim Palfreyman]

The idea is the same as my local telco and their main exchanges.

Every month they walk up to the main circuit breaker and cut the power to
the entire building. All the UPSs and diesel generators get tested in anger.

This leap second solution is the best I've heard so far.

Personally I now hate leap seconds because it ruins many hours of my
observations at the radio telescope - but if this was implemented it would
force the software problems to be fixed.


Jim Palfreyman


On 22 July 2016 at 06:01, Brooke Clarke <bro...@pacific.net> wrote:

> Hi Tom:
>
> I like this idea.  I addresses the lesson from Y2K that something done
> often works much better than something done only occasionally.
> That's way you see the firetruck at the local store, because it's used all
> the time and so is more likely to work when needed.
>
> --
> Have Fun,
>
> Brooke Clarke
> http://www.PRC68.com
> http://www.end2partygovernment.com/2012Issues.html
> The lesser of evils is still evil.
>
>  Original Message 
>
>> Hi Tom...
>>
>> Does your proposal allow for a Zero leap second, or does it require
>> either plus or minus 1 to work? Seems like you could stay closer to the
>> true value if you also have a zero option. Might also cause less
>> consternation for some services, like the finance and scientific worlds,
>> that seem to have critical issues when an LS appears.
>>
>> I like your point that by having it occur monthly it forces systems to
>> address issues promptly, and maybe that's the argument for the non-zero
>> option.
>>
>> Tom Holmes, N8ZM
>>
>>
>> -Original Message-
>> From: time-nuts [mailto:time-nuts-boun...@febo.com] On Behalf Of Tom Van
>> Baak
>> Sent: Thursday, July 21, 2016 1:28 PM
>> To: Discussion of precise time and frequency measurement <
>> time-nuts@febo.com>
>> Cc: Leap Second Discussion List <leaps...@leapsecond.com>
>> Subject: Re: [time-nuts] Leap second to be introduced at midnight UTC
>> December 31 this year
>>
>> Time to mention this again...
>>
>> If we adopted the LSEM (Leap Second Every Month) model then none of this
>> would be a problem. The idea is not to decide *if* there will be leap
>> second, but to force every month to have a leap second. The IERS decision
>> is then what the *sign* of the leap second should be this month.
>>
>> Note this would keep |DUT1| < 1 s as now. UT1 would stay in sync with
>> UTC, not so much by rare steps but by dithering. There would be no change
>> to UTC or timing infrastructure because the definition of UTC already
>> allows for positive or negative leap seconds in any given month.
>>
>> Every UTC-aware device would 1) know how to reliably insert or delete a
>> leap second, because bugs would be found by developers within a month or
>> two, not by end-users years or decades in the future, and 2) every
>> UTC-aware device would have an often tested direct or indirect path to IERS
>> to know what the sign of the leap second will be for the current month.
>>
>> The leap second would then become a normal part of UTC, a regular monthly
>> event, instead of a rare, newsworthy exception. None of the weird bugs we
>> continue to see year after year in leap second handling by NTP and OS's and
>> GPS receiver firmware would occur.
>>
>> Historical leap second tables would consist of little more than 12 bits
>> per year.
>>
>> Moreover, in the next decade or two or three, if we slide into an era
>> where average earth rotation slows from 86400.1 to 86400.0 to 86399.9
>> seconds a day, there will be zero impact if LSEM is already in place.
>>
>> /tvb
>>
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Re: [time-nuts] Visiting Greenwich

[Jim Palfreyman]

Speaking of "speaking clocks" - here's two photos of the ones that used to
be used in Australia:

https://en.wikipedia.org/wiki/Speaking_clock#Australia

The top photo with rotating optical disks is a gorgeous piece of machinery.

The one below - I have one, and I keep it running.

:-)


On 6 July 2016 at 09:30, Clint Jay  wrote:

> Actually,  you're absolutely right,  the speaking clock is on an upper
> gallery display with other timepieces, some of which are amazing.
>
> I've just looked back through my photo gallery and it's the Greenwich time
> service I'm thinking of, a large, five rack wide system that's got (from my
> obviously flaky memory) a Loran receiver and an atomic standard.
>
> Small pic attached.
> On 5 Jul 2016 23:28, "Alan Melia"  wrote:
>
> > Hi Clint I think when I discussed this last a few years ago with the
> > speaking clock designer and David Rooney the man responsible for the time
> > gallery at Greenwich. The clock is an early quartz unit, probably made at
> > the then Post Office Reseach Labs at Dollis Hill in NW London.  The clock
> > is quite a beast ! It was found in a skip (Dumpster) having been donated
> to
> > a university in the late 1940s, and was refurbished by a local enthusiast
> > for David. He did a good job because I believe he had no access to any
> > documents or circuits. I tried to find some information but it would seem
> > the archive has been lost (vandals !!) It probably contains strange
> things
> > like neon ring counters :-))
> >
> > Alan
> > G3NYK
> >
> > - Original Message - From: "Clint Jay" 
> > To: "Discussion of precise time and frequency measurement" <
> > time-nuts@febo.com>
> > Sent: Tuesday, July 05, 2016 9:13 PM
> > Subject: Re: [time-nuts] Visiting Greenwich
> >
> >
> > They also have TIM the speaking clock which has a rack mounted  atomic
> >> standard.
> >> On 5 Jul 2016 21:01, "John Dalziel - crashposition" <
> >> j...@crashposition.com>
> >> wrote:
> >>
> >> I would also recommend the Worshipful Company of Clockmakers collection
> at
> >>> the Science Museum. It’s a great collection and they have some of
> >>> Harrison's wooden long case clocks as well as his final chronometer,
> H5.
> >>>
> >>>
> >>>
> >>>
> http://www.sciencemuseum.org.uk/visitmuseum/plan_your_visit/exhibitions/clockmakers-museum
> >>>
> >>>
> >>> John Dalziel
> >>> computus.org
> >>>
> >>>
> >>> Message: 4
> >>> Date: Mon, 4 Jul 2016 18:31:35 -0400
> >>> From: Dave Martindale 
> >>> To: Discussion of precise time and frequency measurement
> >>> 
> >>> Subject: [time-nuts] Visiting Greenwich
> >>> Message-ID:
> >>> 
> >>> Content-Type: text/plain; charset=UTF-8
> >>>
> >>> I am in London England at the moment, playing tourist with the rest of
> my
> >>> family. I want one day to be a visit to the National Maritime Museum at
> >>> Greenwich, which includes the Royal Observatory Greenwich. I am
> >>> particularly interested in seeing Harrison's H1 through H4, plus other
> >>> high-precision mechanical timekeepers (pendulum clocks, etc).
> >>>
> >>> I know they are at the NMM - their web site shows some of them. But
> where
> >>> are they located on the site? The NMM has a large main building down
> near
> >>> the Thames, while the Royal Observatory and related buildings are on
> the
> >>> top of a hill further inland in Greenwich Park. Are the chronometers
> and
> >>> other precision timekeepers on display somewhere in the Royal
> >>> Observatory,
> >>> or down in the main NMM building? I've spent an hour or two browsing
> web
> >>> sites without finding this particular bit of information.
> >>>
> >>> I figure there must be list members who have visited the NMM, and know
> >>> where the precision timekeepers are actually displayed.
> >>>
> >>> Thanks,
> >>> Dave
> >>> ___
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> >>> To unsubscribe, go to
> >>> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> >>> and follow the instructions there.
> >>>
> >>> ___
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> >>
> >
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Re: [time-nuts] Visiting Greenwich

[Jim Palfreyman]

I was lucky. About ten years ago when visiting I turned up to the Greenwich
Observatory and walked around the corner to see the Harrison clocks.

I didn't know they were there. I didn't know they were anywhere.

I'd read the book, seen the doco, but for some reason assumed they weren't
around any more.

To get a surprise and see them *working* was a great moment in my life.

As David Gilmour once said, "I've never had the pleasure of hearing Dark
Side of the Moon for the first time", well I got the surprise of seeing the
working Harrison clocks - and not knowing it was coming.

Brilliant!


Jim Palfreyman


On 5 July 2016 at 15:00, Peter Monta <pmo...@gmail.com> wrote:

> Hi Dave,
>
> The Harrisons are indeed at the observatory; also look for a regulator
> pendulum clock in the octagon room.  I'm not quite sure whether it was
> running when I was there some years back.
>
> Could it hurt to petition the observatory's powers-that-be for a little hut
> or something at the ITRF meridian?  :-)
>
> If you do get to Bletchley Park, give the National Museum of Computing a
> look-see as well (it's just a short walk).  I believe both facilities have
> benefited from recent infusions of money and support, which is great.
>
> Cheers,
> Peter
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Re: [time-nuts] Maser 0.7 nsec jumps solved

[Jim Palfreyman]

Hold your horses folks.

There is more on this tale!

To recap we put the SSR on the aircon (at zero crossing) and the jumps got
very very worse. So we turned the aircon off again (winter here - so not
really needed) and the jumps dropped, but didn't go away. :-(

So we also have a heater in the room (simple 1200W column heater) and a
temperature monitor that turns the cooling or heating on as appropriate. So
we also replaced the heating relay with an SSR and it all now seems to have
gone away.

We are now thinking that the aircon AND heating *relays* had started to pit
after years of use and so give off radio transients which managed to get in
and interfere with the extremely low (-100 dBm) signal coming from the
physics package and going into the maser electronics.

We have now run for four days with no clock jumps with both aircon and
heater on and with 0V crossing SSR relays.

"Welcome to the jungle, we've got fun and games..."

Jim Palfreyman


On 3 June 2016 at 15:00, Jim Palfreyman <jim77...@gmail.com> wrote:

> Hi All,
>
> Thanks so much for your input and thoughts. It has really proved helpful
> here at the observatory.
>
> As it turned out we easily obtained a zero-crossing solid state relay so
> we thought we'd try it.
>
> And, drumroll..
>
>
>
> It made things so much terribly *worse* than ever before. (As predicted by
> many of you above.)
>
> We are going to try a SSR that switches at the peak - but we need to order
> one. So stay tuned on those results.
>
> There is of course the "move the bloody thing far away from the maser"
> solution which could end up being a serious option. These air conditioning
> units are small and cheap (window-type), so we are trying to find the
> cheapest solution - and if that ends up being some ducting - so be it!
>
>
> Jim Palfreyman
>
>
>
> On 26 May 2016 at 13:13, Andy <ai.egrps...@gmail.com> wrote:
>
>> On Wed, May 25, 2016 at 12:59 PM, Mike Monett <
>> timen...@binsamp.e4ward.com>
>> wrote:
>>
>> LTspice shows  switching  at 0V is the best point in  time.  ...
>>
>>
>>
>> Bzzzt!  Your simulation is seriously flawed, and your conclusions are
>> wrong.  What you forgot, or may not have realized, is that SPICE's initial
>> transient solution is obtained by having the signal sources already turned
>> on (at the moment of the Big Bang) and set to their initial value, so the
>> current through L2 is limited by DC conditions.  That is not anything
>> close
>> to switching the driving voltages on.  It is having one waveform sit at
>> +169.7V DC for a very long time ('forever'), and then letting it follow a
>> cosine wave.
>>
>> Re-run the simulation with "UIC" added to the .tran statement (.tran 50ms
>> uic) and see what it shows.  Using UIC forces the initial voltage to be 0V
>> at time=0, the start of the simulation.  That's like having the switch
>> initially open.
>>
>> Or if you don't like that, multiply the sources by a PWL waveform that
>> starts both voltages at 0V and then switches them on, a few milliseconds
>> into the simulation, with the appropriate phase.
>>
>> Or use an actual switch.  LTspice has a switch element you could use.
>>
>> I guarantee you, the case with the voltage switching on at the 0V point in
>> the voltage waveform, causes greater currents.
>>
>> The smaller surge current happens when the source is connected at the
>> moment when the current i(t) would be 0A if it were a continuous waveform.
>> For an inductive load, this happens when the voltage v(t) would be +/-
>> peak
>> (or near peak, for a real load which has both inductance and a little
>> resistance).  This condition also results in no surge, thus no L/R decay.
>>
>> All of this might not be relevant to a mechanical system, where surge
>> current is caused by rotational inertia, rather than anything electrical.
>>
>> Regards,
>> Andy
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>
>
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Re: [time-nuts] Maser 0.7 nsec jumps solved

[Jim Palfreyman]

Hi All,

Thanks so much for your input and thoughts. It has really proved helpful
here at the observatory.

As it turned out we easily obtained a zero-crossing solid state relay so we
thought we'd try it.

And, drumroll..



It made things so much terribly *worse* than ever before. (As predicted by
many of you above.)

We are going to try a SSR that switches at the peak - but we need to order
one. So stay tuned on those results.

There is of course the "move the bloody thing far away from the maser"
solution which could end up being a serious option. These air conditioning
units are small and cheap (window-type), so we are trying to find the
cheapest solution - and if that ends up being some ducting - so be it!


Jim Palfreyman



On 26 May 2016 at 13:13, Andy <ai.egrps...@gmail.com> wrote:

> On Wed, May 25, 2016 at 12:59 PM, Mike Monett <timen...@binsamp.e4ward.com
> >
> wrote:
>
> LTspice shows  switching  at 0V is the best point in  time.  ...
>
>
>
> Bzzzt!  Your simulation is seriously flawed, and your conclusions are
> wrong.  What you forgot, or may not have realized, is that SPICE's initial
> transient solution is obtained by having the signal sources already turned
> on (at the moment of the Big Bang) and set to their initial value, so the
> current through L2 is limited by DC conditions.  That is not anything close
> to switching the driving voltages on.  It is having one waveform sit at
> +169.7V DC for a very long time ('forever'), and then letting it follow a
> cosine wave.
>
> Re-run the simulation with "UIC" added to the .tran statement (.tran 50ms
> uic) and see what it shows.  Using UIC forces the initial voltage to be 0V
> at time=0, the start of the simulation.  That's like having the switch
> initially open.
>
> Or if you don't like that, multiply the sources by a PWL waveform that
> starts both voltages at 0V and then switches them on, a few milliseconds
> into the simulation, with the appropriate phase.
>
> Or use an actual switch.  LTspice has a switch element you could use.
>
> I guarantee you, the case with the voltage switching on at the 0V point in
> the voltage waveform, causes greater currents.
>
> The smaller surge current happens when the source is connected at the
> moment when the current i(t) would be 0A if it were a continuous waveform.
> For an inductive load, this happens when the voltage v(t) would be +/- peak
> (or near peak, for a real load which has both inductance and a little
> resistance).  This condition also results in no surge, thus no L/R decay.
>
> All of this might not be relevant to a mechanical system, where surge
> current is caused by rotational inertia, rather than anything electrical.
>
> Regards,
> Andy
> ___
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Re: [time-nuts] Maser 0.7 nsec jumps solved

[Jim Palfreyman]

As far as a remedy goes we are going to try a solid state relay that only
switches on at 0V in the AC waveform. This should slow the inrush current,
and hopefully the magnetic impulse.

If this doesn't work, then a better model of air conditioner might have to
be installed. These ones do come on with a big "thump".


Jim Palfreyman


On 22 May 2016 at 21:43, Magnus Danielson <mag...@rubidium.dyndns.org>
wrote:

> Jim,
>
> On 05/22/2016 03:58 AM, Jim Palfreyman wrote:
>
>> Hi all,
>>
>> Awhile back I posted about some mysterious 0.7 ns jumps in three different
>> masers (of the same brand) at three different locations around Australia.
>>
>> Well we think we've found the problem. All three locations also have
>> in-room air conditioners of the same brand. These are used for cooling
>> only. When these units turn on, we think they induce a magnetic field from
>> the inrush current that briefly disrupts the maser. We don't think it's
>> electrical because moving to another phase did not change things.
>>
>> These air conditioners are all quite close to the masers. Typically a
>> metre
>> or 2 away.
>>
>> Much was done to discover this, but the clincher was that when the weather
>> cooled enough at the southern most location (Hobart), we turned off the
>> air
>> con (only heating was needed) and the problem vanished.
>>
>> So there's a lesson here for all maser owners. The jump of 0.7 nsec is not
>> much, but it's huge for VLBI and for time-nuts.
>>
>
> Good that you have found the offender, but have you been able to remedy it
> by other means than turning the AC off?
> I think others H-maser owners would love to know, and potentially the
> vendor you have.
>
> Cheers,
> Magnus
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[time-nuts] Maser 0.7 nsec jumps solved

[Jim Palfreyman]

Hi all,

Awhile back I posted about some mysterious 0.7 ns jumps in three different
masers (of the same brand) at three different locations around Australia.

Well we think we've found the problem. All three locations also have
in-room air conditioners of the same brand. These are used for cooling
only. When these units turn on, we think they induce a magnetic field from
the inrush current that briefly disrupts the maser. We don't think it's
electrical because moving to another phase did not change things.

These air conditioners are all quite close to the masers. Typically a metre
or 2 away.

Much was done to discover this, but the clincher was that when the weather
cooled enough at the southern most location (Hobart), we turned off the air
con (only heating was needed) and the problem vanished.

So there's a lesson here for all maser owners. The jump of 0.7 nsec is not
much, but it's huge for VLBI and for time-nuts.


Jim Palfreyman
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Re: [time-nuts] Unix software to generate nice looking *DEV plots

[Jim Palfreyman]

R might be a good place to start.

I use it extensively for astrophysics (all graphs in my recent pulsar paper
accepted in The Astrophysical Journal were done using R:
http://arxiv.org/pdf/1602.01899v1.pdf).

R has a huge support network. I haven't even looked, but I bet it'd be a
great place to start.

And it's free.

As an aside, fellow time-nuts may be interested in the paper. It's mostly
about timing after all.


Jim Palfreyman


On 17 March 2016 at 21:29, Attila Kinali <att...@kinali.ch> wrote:

> Moin,
>
> I'm looking for some non-GUI software to generate the different *DEV
> plots we generally use to asses oscillators with. Timelab is nice,
> but if you are evaluating two dozen measurements using different
> parameters, it becomes very tedious to generate the plots. Not
> to talk about the problem that the plots are not really reproducable,
> which is a very important property, when publishing results.
>
> I could for sure write myself wrappers around
> gnuplot/ploticus/mathplotlib/..
> to generate the *DEV plots, but I'm not keen on reinventing the wheel.
>
> Thus I'd like to ask whether someone has any hints on what to use.
>
> Attila Kinali
>
> --
> It is upon moral qualities that a society is ultimately founded. All
> the prosperity and technological sophistication in the world is of no
> use without that foundation.
>  -- Miss Matheson, The Diamond Age, Neil Stephenson
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Re: [time-nuts] HP5370B & HP5345B Front-End IC Redesign Effort

[Jim Palfreyman]

Hi Mathew,

As someone who just lost their stop channel, I'm extremely interested in
this project!

Jim Palfreyman


On 23 January 2016 at 09:14, Mathew Breton <ab...@outlook.com> wrote:

> I was gifted an HP 5370B with the usual problem: front-end problems,
> probably due to overstress. It is currently up and running again with a set
> of 5345A series A3/A4 boards as I wasn't able to get a cheap pair of
> 5088-706x hybrid ICs.
> This sounds like a common problem. As a result, I'm designing an
> open-source drop-in (hopefully) replacement. My hat is off to the original
> IC designer, as it is not a trivial effort due to the wide input signal
> common-mode range, and very tight trigger timing requirements. Other items
> (like the E-ECL) output) are also adding a bit of extra effort.
> I'm hoping that someone(s) might be interested in working with me on it. I
> would like to have my assumptions and math checked before I start the
> detailed design phase, and perhaps contribute some better ideas.
> In addition, it would be really helpful if someone could run a few
> rise-time dispersion tests on an instrument with a working "B"-series A3/A4
> PCB set (my unit obviously doesn't qualify).
> Regards,
> Mat Breton
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Re: [time-nuts] 5370B stop trigger not working

[Jim Palfreyman]

Thanks Chris.

I'm beginning to think my 5370B is heading towards a boat anchor.

We (as in all time-nut owners of 5370s) seriously need to research a
replacement part/circuit for the 7061/7062 parts.


Jim


On 22 December 2015 at 07:44, Christopher E. Brown <cbr...@woods.net> wrote:

>
> You might want to re-scope the start and stop channel outputs where they
> cross A4 and
> verify against the front panel labels.
>
> The signal line crossing A4 that lines up with frontpanel start is start
> and the one that
> lines up with stop is stop.
>
>
> I mention this because the A3 board is a carry over from another unit and
> the start/stop
> labeling on the board itself is reversed from the 5370B front panel labels
> and the parts
> list follows the board labeling.  So, if you read front panel and lookup
> P/N in list you
> get the wrong one.
>
>
> The safe thing is to follow back from the output crossing A4 that is
> failing and
> physically pull the hybrid and read the P/N on the mounting frame.  It
> should be a metal
> can in a screw together frame, the part is socketed.
>
>
> Once the A3 is out, do not remove the screws in frame, they just clamp the
> frame to part.
>  Whole thing is held in by the collar on the pot shaft.
>
>
> For a 5370B
>
> 5088-7061 (start channel hybrid)
> 5088-7062 (stop channel hybrid)
>
> the manual lists it reversed, and they are actually different parts (not
> just diff
> mounting frames) with crossed up triggers.
>
>
> 7061 (actual start manual lists as stop) is the one that usually fails and
> is almost
> impossible to find.  Took me several years (and the help of another nut
> with a parts unit)
> to get a working one.  7062 is much easier to find.
>
>
> On 12/13/2015 11:26 AM, Jim Palfreyman wrote:
> > Oops yes! I looked up the wrong item. I meant A3U1 which is 5088-7061
> >
> > Jim
> >
> >
> > On Sunday, 13 December 2015, Cok <electron...@jpkoning.nl> wrote:
> >
> >> According to the partlist A4U1 and A4U2 seems to be TL072CP opamps.
> >>
> >>>
> >>> jim77...@gmail.com said:
> >>>
> >>>> I have gone through the troubleshooting process from the manual and it
> >>>> seems
> >>>> to point to A4U2 (Schmidt trigger) being faulty.
> >>>>
> >>> I'd put a scope on it to check.
> >>>
> >>> Before I dive into this, does anyone have any advice? Most important
> being
> >>>> the Schmidt trigger - where do I get one?
> >>>>
> >>> You need more info - the manufacturer's part number or something like
> >>> that.
> >>>
> >>>
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Re: [time-nuts] 5370B stop trigger not working

[Jim Palfreyman]

Yes I've been through the process in the service manual with an
oscilloscope and the part number of the Schmitt trigger (apologies for the
auto-corrected spelling above) is TL072CP.

What I'm after is any "gotchas" or hints before I head down this path.


Jim Palfreyman


On 13 December 2015 at 18:06, Hal Murray <hmur...@megapathdsl.net> wrote:

>
>
> jim77...@gmail.com said:
> > I have gone through the troubleshooting process from the manual and it
> seems
> > to point to A4U2 (Schmidt trigger) being faulty.
>
> I'd put a scope on it to check.
>
> > Before I dive into this, does anyone have any advice? Most important
> being
> > the Schmidt trigger - where do I get one?
>
> You need more info - the manufacturer's part number or something like that.
>
> --
> These are my opinions.  I hate spam.
>
>
>
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Re: [time-nuts] 5370B stop trigger not working

[Jim Palfreyman]

Oops yes! I looked up the wrong item. I meant A3U1 which is 5088-7061

Jim


On Sunday, 13 December 2015, Cok  wrote:

> According to the partlist A4U1 and A4U2 seems to be TL072CP opamps.
>
>>
>> jim77...@gmail.com said:
>>
>>> I have gone through the troubleshooting process from the manual and it
>>> seems
>>> to point to A4U2 (Schmidt trigger) being faulty.
>>>
>> I'd put a scope on it to check.
>>
>> Before I dive into this, does anyone have any advice? Most important being
>>> the Schmidt trigger - where do I get one?
>>>
>> You need more info - the manufacturer's part number or something like
>> that.
>>
>>
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[time-nuts] 5370B stop trigger not working

[Jim Palfreyman]

Hi all,

My stop trigger has stopped working on my 5370B (a while back - just
getting around to fixing it).

I have gone through the troubleshooting process from the manual and it
seems to point to A4U2 (Schmidt trigger) being faulty.

Fixing this looks like a decent job of: sourcing a part, removing the front
panel, removing board A4, desoldering, and reassembling.

Before I dive into this, does anyone have any advice? Most important being
the Schmidt trigger - where do I get one?


Regards,

Jim Palfreyman
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[time-nuts] Hydrogen maser frequency jumps

[Jim Palfreyman]

Hi all,

Has anyone here who is familiar with hydrogen masers ever experienced a
sudden jump in phase of the 5MHz output?

We have found they occur semi-regularly (few times a week) and are trying
to find a culprit.

The weird thing is that the jump is ~0.7ns and that 1/0.7E-9 is close-ish
to 1420.4MHz which is the hydrogen line. Too much of a coincidence for me.

These seem to be appearing at three different locations with the same model
of maser at each location. I won't mention the model publicly.

We're still investigating various potential causes (e.g. power spikes,
cables being moved), but this 0.7ns figure is niggling me.

Has anyone here ever seen such a thing before?


Jim
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Re: [time-nuts] [volt-nuts] The Art of Electronics

[Jim Palfreyman]

What's been added? This is a brilliant book, but I need to know what the
updates are!

Jim


On 17 April 2015 at 18:12, Poul-Henning Kamp p...@phk.freebsd.dk wrote:

 
 In message 20150417074427.ga31...@sol.ermione.com, Andrea Baldoni
 writes:

 Hello.
 In the case someone missed the new, after years of waiting, the third
 edition
 of the book in the subject is out!

 I received it last week, and yes, it's absolutely worth the money.


 --
 Poul-Henning Kamp   | UNIX since Zilog Zeus 3.20
 p...@freebsd.org | TCP/IP since RFC 956
 FreeBSD committer   | BSD since 4.3-tahoe
 Never attribute to malice what can adequately be explained by incompetence.
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[time-nuts] 5370B stop port has died

[Jim Palfreyman]

My Stop port has just stopped working. The light is on all the time.

I installed the Beaglebone CPU a few months back. Is there a chance it
could be a software issue causing it?

(I will re-install the original CPU to test - but I was wondering if anyone
else had a similar problem.)

Jim Palfreyman
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Re: [time-nuts] 5370B stop port has died

[Jim Palfreyman]

The last thing I had connected was the 1PPS output from a 5065A rubidium. I
had the 5370B on 1 Megohm (I never use the internal 50 Ohm termination
because of the risk of damage) so I assumed it would be fine.

I've done this heaps of times before too.

Jim Palfreyman


On 20 October 2014 12:10, Bob Camp kb...@n1k.org wrote:

 Hi

 One of the classic ways to kill most of the 53xx boxes is to put a DC
 voltage on the input with the attenuator set to zero. 5335’s very much did
 not like a 5V level on the input. I spent more money replacing front end
 boards than I did on the counters when we bought them. I never looked to
 see if the 5370 shared that “feature” or not. I also never tried
 overloading mine.

 Bob

  On Oct 19, 2014, at 8:49 PM, Jim Palfreyman jim77...@gmail.com wrote:
 
  My Stop port has just stopped working. The light is on all the time.
 
  I installed the Beaglebone CPU a few months back. Is there a chance it
  could be a software issue causing it?
 
  (I will re-install the original CPU to test - but I was wondering if
 anyone
  else had a similar problem.)
 
  Jim Palfreyman
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Re: [time-nuts] GPS jump

[Jim Palfreyman]

http://users.on.net/~cdadsl/

Is a web page with all our different sites on it.

Hobart 26m seems to be the only exception but I did make an adjustment on
that day. But the adjustment didn't appear.

All sites are collected and analysed separately with their own GPS clock.
Some are old TACs and most are CNS mark II.

It could be a fluke, but it does seem weird. And as was pointed out - this
happened last year at around the same time. Well spotted Mike Cook!



On 11 October 2014 09:54, Tom Van Baak t...@leapsecond.com wrote:

 Hi Jim,

 Can you tell me more about your configuration? What GPS receiver / antenna
 system do you use; L1 or L1/L2? Is this live 1PPS data, or post-processed
 from RINEX, etc. Is the data analysis done separately in 5 locations or is
 the raw data collected and processed together.

 Through IGS and NASA and BIPM there's GPS and maser data from all over the
 world so it should be possible to track this down. I can ask people I know
 too. But can you clarify how much the downward turn is? Is that ps/day,
 or ns/day, or what.

 Thanks,
 /tvb

 - Original Message -
 From: Jim Palfreyman jim77...@gmail.com
 To: Discussion of precise time and frequency measurement 
 time-nuts@febo.com
 Sent: Thursday, October 09, 2014 4:43 PM
 Subject: [time-nuts] GPS jump


  Folks,
 
  We look after 5 separate hydrogen masers spread all over Australia and we
  collect tic phases between the masers and the GPS.
 
  On around ~Oct 7 we have noticed that the normal steady straight line
 (with
  standard daily noise) took a noticeable downward turn - on all 5 masers.
 
  Did anyone else who tracks H-masers notice this as well?
 
  Is it JPL making corrections?
 
 
  Jim Palfreyman
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[time-nuts] GPS jump

[Jim Palfreyman]

Folks,

We look after 5 separate hydrogen masers spread all over Australia and we
collect tic phases between the masers and the GPS.

On around ~Oct 7 we have noticed that the normal steady straight line (with
standard daily noise) took a noticeable downward turn - on all 5 masers.

Did anyone else who tracks H-masers notice this as well?

Is it JPL making corrections?


Jim Palfreyman
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Re: [time-nuts] Symmetricom chip scale atomic clock

[Jim Palfreyman]

Out of curiosity, what's the current price for one of these for a time-nut
to play with?

Regards,

Jim Palfreyman



On 25 April 2014 11:26, Said Jackson saidj...@aol.com wrote:

 Hi Magnus, Bob,

 Thanks much for your kind words.

 The failure rate is thankfully so low that we are not greatly alarmed, and
 Microsemi has been a champ in resolving any failures with/for us when they
 did show up. We are awaiting the results of the full re-qualify that
 Microsemi is doing on the CSAC and were going to announce the issue at that
 time..

 Bye,
 Said

 Sent From iPhone

 On Apr 24, 2014, at 17:41, Bob Camp li...@rtty.us wrote:

  Hi
 
  I seem to have been in exactly the same position many times before and
 also wish you well in resolving this (as I’m *certain* will be the case).
 
  Bob
 
  On Apr 24, 2014, at 7:48 PM, Magnus Danielson 
 mag...@rubidium.dyndns.org wrote:
 
  Said,
 
  I recognize this situation so well. Feel with you on the issue and hope
 you find that it resolve itself nicely.
 
  Cheers,
  Magnus
 
  On 04/24/2014 10:50 PM, saidj...@aol.com wrote:
  Hello everyone,
 
  let me address the below claims and commentary which was posted without
  first consulting with us.
 
  Microsemi has recently seen a slightly higher failure rate of the CSAC
  oscillators than expected. A small percentage of our customers have
 been
  adversely affected by this issue. We have been, and will continue to
 take care
  of this issue when it happens to units we sold by doing a warranty
 exchange
  of  the CSAC for the affected customer unit, even if it should fall
 out of
  its normal warranty period.
 
  We believe in supporting our customers to the maximum extent possible,
 and
  of course want to deliver a product that has the highest level of
 quality
  possible. That said, we must remember that the CSAC technology is a
 ground
  breaking, never-before-done in commercial quantities, absolutely new
 type of
  oscillator technology, and being at the forefront of such a technology
  sometimes  means there is a bit of a learning curve to deal with. This
 is one
  of the main  reasons why no one else in the world besides Microsemi
 makes
  CSAC type products  for commercial sale.
 
  So all in all, if a customer unit should get affected by this problem
 then
  the issue will be addressed by us and Microsemi with a quick turn
 around
  and a no questions asked approach, and we hope that this approach
 sets us
  positively apart from the competition.
 
  Lastly, we received the below comments/explanation from Microsemi
  about
  this issue which we have permission to share with you, and this
  should help
  alleviate the problem for new orders.
 
  Sincerely,
  Said
 
 
 
  
  Some Symmetricom (now  Microsemi) Chip Scale Atomic Clocks have shown a
  failure mode that will manifest  itself as an inability of the clock
 to achieve
  atomic lock.  If the CSAC’s  telemetry string is monitored, the failure
  mode will show up as a Status Level  8.  Microsemi’s investigation
 into the
  problem uncovered three distinct  root causes, although the symptom
 the user
  observes is always a Status Level 8,  regardless of which root cause
 is the
  underlying issue.  It is important to  note that all three root causes
 are
  process issues, not design  issues.
  All three root causes  have been addressed, and Microsemi is currently
  producing CSAC’s with all three  fixes implemented.  A full
 re-qualification of
  the CSAC is also being done,  to ensure that the fixes are effective.
  CSAC’
  s already in the field that  exhibit this failure mode have been, and
 will
  continue to be, replaced under  warranty.
 
 
  
 
 
  In a message dated 4/24/2014 10:16:25 Pacific Daylight Time,
  les...@veenstras.com writes:
 
 
  Affected Products: Jackson Labs or Symmetricom time/frequency
  reference
  boards based on Symmetricom chip scale atomic  clock
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Re: [time-nuts] quartz clock/watch question

[Jim Palfreyman]

I've opened up my Casio G-Shock watch, found an electrical point, put an
oscilloscope on it and successfully adjusted it. From memory the frequency
was something weird, but I still tuned it successfully to within about a
second a month. I even think I posted to time-nuts on this...

Jim Palfreyman



On 19 April 2014 09:25, Bob Albert bob91...@yahoo.com wrote:

 I have tried to pick up the oscillator from my wristwatch and have been
 unsuccessful.


 I tried both magnetic and electric probes.  Nothing.

 Bob

 On Friday, April 18, 2014 4:12 PM, Tom Van Baak t...@leapsecond.com
 wrote:

  When a quartz watch or clock is assembled, what method is used to get it
 as accurate as possible?

 Bob,

 First generation quartz watches had a tiny F/S (fast/slow) trimmer
 capacitor. These days it's done with skip cycles and one-time factory
 calibration. Think leap days or leap seconds -- it's easier and more
 reliable than changing the frequency of the oscillator itself. It's also
 one less part, easier to calibrate, and unlike active and passive
 components, math has no environmental sensitivity.

 Have a quick read of 32 kHz watch IC's like:
 http://www.nxp.com/documents/data_sheet/PCA2000_2001.pdf

 /tvb


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Re: [time-nuts] GPS to H-Maser comparison

[Jim Palfreyman]

Maybe Australia was mainly hit by the CME?

On Sunday, 6 October 2013, Said Jackson wrote:

 Zero effect visible on the CSAC GPSDO real time plots from our lab:

 http://www.jackson-labs.com/images/gpsstat.htm

 Sent From iPhone

 On Oct 3, 2013, at 20:56, Jim Palfreyman jim77...@gmail.comjavascript:;
 wrote:

  Hi all,
 
  If you go to this page: http://users.on.net/~cdadsl/ you will see some
  graphs (all in UT). Notice the larger than usual bump on Oct 02 around
 0600
  ish. The names are locations all over Australia.
 
  Jim Palfreyman
 
 
  On Friday, 4 October 2013, Brian Inglis wrote:
 
  On 2013-10-03 05:33, Jim Palfreyman wrote:
 
  Noticed an above average bump in our H-Maser vs GPS graphs - from sites
  all
  over Australia.
 
  Recent coronal mass ejection or US government shutdown not updating
 GPS?
 
  Anyone else seen it?
 
 
  drop out gap between about 04.21-04.26 UTC?
  clockstats.20131003:
  56568 15684.876 127.127.20.4 $GPRMC 042124 A ...
  56568 16004.862 127.127.20.4 $GPRMC 042644 A ...
  peerstats.20131003:
  56568 15684.876 127.127.20.4 961a -0.02270 ... 0.05344
  56568 16004.862 127.127.20.4 961a -0.13150 ... 0.15721
  loopstats.20131003:
  56568 15684.876 -0.02270 0.899 0.07071 0.70 4
  56568 16004.862 -0.13150 0.898 0.08830 0.000114 4
 
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Re: [time-nuts] GPS to H-Maser comparison

[Jim Palfreyman]

Well it cannot be local. These sites span Australia. The masers are
different brands too.

The massive CME seems to be the culprit:

Breaking the quiet in spectacular fashion, a magnetic filament erupted from
the sun's northern hemisphere at approximately 2145 UT on Sept. 29th.
NASA's Solar Dynamics Observatory recorded the blast.

applewebdata://91B0A590-C320-4B10-B39D-1D6B397C2F2D/images2013/30sep13/ipad/magnificent.m4v

The explosion hurled a magnificent
CMEapplewebdata://91B0A590-C320-4B10-B39D-1D6B397C2F2D/images2013/30sep13/cme.jpg
into
space. The magnetized cloud, which left the sun traveling approximately 900
km/s, was not aimed toward Earth. Nevertheless, out planet's magnetosphere
might receive a glancing blow on Oct. 2-3. Polar geomagnetic storms and
auroras are possible when the CME arrives. Stay tuned for updates.

On Sunday, 6 October 2013, mc235960 wrote:


 Le 5 oct. 2013 à 18:15, Magnus Danielson a écrit :

  On 10/03/2013 01:33 PM, Jim Palfreyman wrote:
  Noticed an above average bump in our H-Maser vs GPS graphs - from sites
 all
  over Australia.
 
  Recent coronal mass ejection or US government shutdown not updating GPS?
  Considering that GPS Operational Advisery messages have been sent out as
  regular, and the critical level of the system, it's hardly likely. You
  will have to look elsewhere. Local issues are more likely.

   I doubt this as at least two of the sites showing the anomaly are around
 3000km distant. I was wondering whether it might be due to grid issues, but
 the western australian grid has no connection to that covering the eastern
 states. I suppose it could be an admin foulup if the GPS receivers are all
 web administered.

 
  Cheers,
  Magnus
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[time-nuts] GPS to H-Maser comparison

[Jim Palfreyman]

Noticed an above average bump in our H-Maser vs GPS graphs - from sites all
over Australia.

Recent coronal mass ejection or US government shutdown not updating GPS?

Anyone else seen it?

Jim Palfreyman
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Re: [time-nuts] GPS to H-Maser comparison

[Jim Palfreyman]

Hi all,

If you go to this page: http://users.on.net/~cdadsl/ you will see some
graphs (all in UT). Notice the larger than usual bump on Oct 02 around 0600
ish. The names are locations all over Australia.

Jim Palfreyman


On Friday, 4 October 2013, Brian Inglis wrote:

 On 2013-10-03 05:33, Jim Palfreyman wrote:

 Noticed an above average bump in our H-Maser vs GPS graphs - from sites
 all
 over Australia.

 Recent coronal mass ejection or US government shutdown not updating GPS?

 Anyone else seen it?


 drop out gap between about 04.21-04.26 UTC?
 clockstats.20131003:
 56568 15684.876 127.127.20.4 $GPRMC 042124 A ...
 56568 16004.862 127.127.20.4 $GPRMC 042644 A ...
 peerstats.20131003:
 56568 15684.876 127.127.20.4 961a -0.02270 ... 0.05344
 56568 16004.862 127.127.20.4 961a -0.13150 ... 0.15721
 loopstats.20131003:
 56568 15684.876 -0.02270 0.899 0.07071 0.70 4
 56568 16004.862 -0.13150 0.898 0.08830 0.000114 4

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Re: [time-nuts] OT Prototype Boards

[Jim Palfreyman]

Oh dear. Please go metric US. Please.

We will help you.

Jim



On 27 June 2013 11:33, Hal Murray hmur...@megapathdsl.net wrote:


 j...@quikus.com said:
  There WERE (past tense) a number of definitions of the inch, ranging from
  lines on bars of PtIr to a string of grain kernels.

  Now there IS (present tense) one, defined as 2.54 cm.

 Except...

 http://en.wikipedia.org/wiki/Foot_%28unit%29#International_foot

 When the international foot was defined in 1959, a great deal of survey
 data
 was already available based on the former definitions, especially in the
 United States and in India. The small difference between the survey and the
 international foot would not be detectable on a survey of a small parcel,
 but
 becomes significant for mapping, or when the state plane coordinate system
 is
 used in the US, because the origin of the system may be hundreds of
 thousands
 of feet (hundreds of miles) from the point of interest. Hence the previous
 definitions continued to be used for surveying in the United States and
 India
 for many years, and are denoted survey feet to distinguish them from the
 international foot. The United Kingdom was unaffected by this problem, as
 the
 retriangulation of Great Britain (1936-62) had been done in meters.

 The United States survey foot is defined as exactly 1200/3937 meter,
 approximately 0.3048006096 m.[

 --
 These are my opinions.  I hate spam.



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[time-nuts] Measuring speed of light or reproducing a metre

[Jim Palfreyman]

Hi all,

With a 3325B, a 5370B, and other time-nut miscellany, what's the quickest
way you can come up with to measure the speed of light OR reproduce the
metre.

I've got some ideas, but I'd like others' thoughts.

Jim
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Re: [time-nuts] Measuring speed of light or reproducing a metre

[Jim Palfreyman]

My actual application is as a quick cool demo showing what I can do with
this gear in my garage when people go why?

:-)



On 24 June 2013 09:22, Magnus Danielson mag...@rubidium.dyndns.org wrote:

 Hi Jim,


 On 06/24/2013 01:03 AM, Jim Palfreyman wrote:

 Hi all,

 With a 3325B, a 5370B, and other time-nut miscellany, what's the quickest
 way you can come up with to measure the speed of light OR reproduce the
 metre.

 I've got some ideas, but I'd like others' thoughts.


 Using a laser that reflects and a detector, create a resonator, such that
 the received signal is amplified and modulated on the laser.
 The delay through the circuit needs to be calibrated, but once you have
 done that, you remove it from the measured period of this oscillator, and
 the remaining time will be the flight-time. Using a TIC like the 5370B you
 can measure this period with a fairly high resolution, averaging and all.
 Recall that the flight-time will for twice the distance. This setup isn't
 perfect in many senses, but you can do it.
 The 3325B might come handy in calibration.

 By intentionally insert extra delay (which we assume is stable and known)
 you can reduce the range of frequency and hence phase shift variation
 needed to be calibrated, which can increase the precision to some point.

 This is a rough method of doing it, but it may serve your needs
 sufficiently good. I could probably hack this up with scraps lying around
 my lab, possibly lacking the optics for the laser.

 What is your actual application?

 Cheers,
 Magnus
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[time-nuts] +/- TI button on 5370B

[Jim Palfreyman]

Folks,

I'm struggling to understand this button and how it reports intervals. It's
supposed to show negative when the Stop is before the Start.

When I connect up two clocks sending out 1PPS and say the one connected to
Stop is ahead then sometimes I'd get -123.45 ns (say) and sometimes it
flips to 999.999... ms. It can't seem to make up its mind which to use.

Why is this inconsistent?

If I flip it to + TI and make sure the leading clock is on Start - all
works well.

Thoughts?

Jim Palfreyman
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Re: [time-nuts] HP5065B !!!

[Jim Palfreyman]

Am I missing something? What actual modifications were done and how?

Jim



On 1 May 2013 07:30, ewkeh...@aol.com wrote:

 Attilla
 No  one should or will discourage you from developing a laser pumped  Rb.
 Bruce posted the following link. It addresses some of the issues and for me
 looking at lamp Rb's is most helpful.

 http://tf.boulder.nist.gov/general/pdf/1219.pdf

 Bert Kehren



 In a message dated 4/30/2013 4:51:57 P.M. Eastern Daylight Time,
 att...@kinali.ch writes:

 On Mon,  29 Apr 2013 17:19:05 -0400 (EDT)
 ewkeh...@aol.com wrote:

  I am  still sitting here trying to figure out the purpose  of posting the

  article on laser diode pumping of the Rb. One look at the data   and it
 is
  clear that Corby’s work far surpasses the data shown in the  paper. All
 it does
  is distract from Corb’s  accomplishments.

 Sorry i didnt mean to do that. I am very gratefull at  the work Corby
 has done and the new insights on what error sources a Rb gas  cell
 has.

 But as someone living in europe, i have certain problems  getting my
 hands on a HP5065. There is virtually no surplus market here.  And
 if there is anything sold in europe, the price is nearly that of
 a  new device, sometimes even more (no, i'm neither joking nor
 exagerating).
 I  cannot buy any of the fancy devices you have access to in the US.
 Buying a  Cs beam, as a few of you have, is a dream that will not come
 true for me,  unless i win in the lottery.
 But building my own Rb standard using laser  diodes is feasible.
 I still lack a lot of knowledge and understanding how  to do that,
 but this group has been very helpfull in filling my gaps, when  asking
 the right questions. And if you don't mind, i would like to  keep
 asking those questions.


 Attila Kinali
 --
 The people on 4chan are like brilliant  psychologists
 who also happen to be insane and gross.
 --  unknown
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Re: [time-nuts] Time nut newbie

[Jim Palfreyman]

Buy a cheap rubidium off ebay and use it to drive a micro-controller and
write some clock software.


On 1 May 2013 11:57, Rex r...@sonic.net wrote:

 It doesn't affect the general magnitude conclusions by Bruce, but as long
 as we are making corrections, my calculator seems to think
 60 * 60 * 24 * 12 = 1036800 seconds in 12 days, not 1024800.  That does
 come out to 115.7 days for 1 sec error. Maybe the 12-day number was a typo?

 -Rex



 On 4/30/2013 12:57 PM, Bruce Griffiths wrote:

 12 days is 1024800 s ie just over 1 million seconds so a frequency offset
 of 0.1ppm results in a time error of ~ 0.1s not 1s.
 1sec error would occur in just under 116 days,

 Bruce

 Bob Camp wrote:

 Hi

 If you take a look down in the fine print on the OCXO spec, the aging
 rate
 is 100 ppb / year in the first year. If you are off by 0.1 ppm (100 ppb)
 your clock will gain a second in less than 12 days.

 Bob


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Re: [time-nuts] HP5065B !!!

[Jim Palfreyman]

Hi,

Where are the details of the changes and how to do them?

Jim


On Saturday, 27 April 2013, John Miles wrote:

 Very nice bit of RD work on Corby's part.  Mine is certainly working well
 after the modification, but I'm just blown away at the performance seen
 with
 Tom's unit.

 Another plot of the Super mod that's worth mentioning:
 http://www.ke5fx.com/5065A_vs_maser_mask.png

 Below 1000 seconds it has no trouble passing the spec limits for a passive
 H-maser!  For contrast, teeypical LPRO-101 performance is shown in green,
 and the red trace is from the second-best commercial Rb standard I've seen
 (Symmetricom XPRO).

 -- john, KE5FX
 Miles Design LLC


  -Original Message-
  From: time-nuts-boun...@febo.com javascript:; 
  [mailto:time-nuts-javascript:;
  boun...@febo.com javascript:;] On Behalf Of cdel...@juno.comjavascript:;
  Sent: Friday, April 26, 2013 8:24 AM
  To: time-nuts@febo.com javascript:;
  Subject: [time-nuts] HP5065B !!!
 
  OK, that was just to get your attention!
 
  What do you call a modified HP 5065A that can give you an Allan Deviation
  of 4X10-13 @ 1 Second and 6X10-14 @ 100 Second?
 
  I call it the SUPER HP 5065A.
 
  Any of these links will get you to the document describing it.
 
  Have a look and see what it's all about!
 
  Enjoy,
 
  Corby
 
 
  http://leapsecond.com/corby/Super-5065A-Project.pdf
 
  or
 
  http://leapsecond.com/corby/superproj10.docx
 
  or
 
  http://www.febo.com/pages/HP5065A_SUPER for
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[time-nuts] Leap second? Yay or nay?

[Jim Palfreyman]

As an astronomer I've been a supporter of the current leap second situation
and have not really liked the idea of changing.

However, after yesterday I'm thinking of changing my mind.

I quite enjoyed having to go through and change all my clocks (including a
pendulum clock - now that's a pain!), but then the news came through that
Amadeus crashed worldwide. Passengers everywhere were left stranded for
hours because of this.

Y2K all over again - but this time something big happened.

This could also have been serious. Were planes tested in-flight for this? I
bet they weren't.

Software writers the world over are notorious for not fully testing their
code, so the leap second situation in our increasingly time-dependent world
has the potential to one day take a life.

Maybe it is time to swallow this bitter pill and remove the leap second.

I haven't jumped ship yet - but I'm very very close.

Thoughts?

Jim Palfreyman
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Re: [time-nuts] Leap second? Yay or nay?

[Jim Palfreyman]

With a large correction then maybe people would take it more seriously like
they did Y2K?


On 2 July 2012 11:03, Brooke Clarke bro...@pacific.net wrote:

 Hi Jim:

 Would you rather have these minor problems or have a much bigger one when
 they make a larger correction?
 That's assuming that the leap second would be replaced by the leap minute
 or something similar on a larger time scale so that the the time had some
 relationship to the Earth's rotation.

 Have Fun,

 Brooke Clarke
 http://www.PRC68.com
 http://www.**end2partygovernment.com/**2012Issues.htmlhttp://www.end2partygovernment.com/2012Issues.html

 Jim Palfreyman wrote:

 As an astronomer I've been a supporter of the current leap second
 situation
 and have not really liked the idea of changing.

 However, after yesterday I'm thinking of changing my mind.

 I quite enjoyed having to go through and change all my clocks (including a
 pendulum clock - now that's a pain!), but then the news came through that
 Amadeus crashed worldwide. Passengers everywhere were left stranded for
 hours because of this.

 Y2K all over again - but this time something big happened.

 This could also have been serious. Were planes tested in-flight for this?
 I
 bet they weren't.

 Software writers the world over are notorious for not fully testing their
 code, so the leap second situation in our increasingly time-dependent
 world
 has the potential to one day take a life.

 Maybe it is time to swallow this bitter pill and remove the leap second.

 I haven't jumped ship yet - but I'm very very close.

 Thoughts?

 Jim Palfreyman
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Re: [time-nuts] Paywall rant

[Jim Palfreyman]

I'm in astrophysics and arXiv is there just for that.

Why don't others do that?

Jim


On Tuesday, 5 June 2012, Attila Kinali wrote:

 On Tue, 05 Jun 2012 00:26:56 -0700
 Hal Murray hmur...@megapathdsl.net javascript:; wrote:

  The IEEE is particularly behind the times.  I assume it's left over from
 when
  they could get away with it because they only had to jack up the price of
  printed stuff by a small amount.  Some of this may trace back to their
  standards work where they could get away with high prices.

 Actually they are getting worse. IEEEs Computer Society started to send
 out yearly reminders that it's not ok to share documents you legaly
 acuired with your coworkers and friends. Telling them a few times that
 this is in contradiction to local law, which explicitly allows me to do
 that didn't change anything... That and also the wording that strongly
 suggests that anyone who is subscribed to the CDL is a thief (illegaly
 copying files and sharing them with the world) led me to the decision
 to cancel my subscription.


Attila Kinali
 --
 It is upon moral qualities that a society is ultimately founded. All
 the prosperity and technological sophistication in the world is of no
 use without that foundation.
 -- Miss Matheson, The Diamond Age, Neil Stephenson

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Re: [time-nuts] NIST Time and Frequency Metrology Seminar

[Jim Palfreyman]

By announcing and bragging we expect a full and detailed report!

On Wednesday, 16 May 2012, John Miles wrote:

 I'll be there as well.  Glad to hear so many folks from the list are able
 to
 make the journey!

 -- john

  -Original Message-
  From: time-nuts-boun...@febo.com javascript:; [mailto:
 time-nuts-boun...@febo.com javascript:;] On
  Behalf Of Magnus Danielson
  Sent: Wednesday, May 16, 2012 12:54 AM
  To: time-nuts@febo.com javascript:;
  Subject: Re: [time-nuts] NIST Time and Frequency Metrology Seminar
 
  Dave,
 
  On 05/16/2012 03:14 AM, David Bengtson wrote:
   I'll also be there for the seminar.
 
  Cool! See you there.
 
  As I mentioned in an off-list mail, I have some spare days so I will try
  to use them to get out a little. Considering visiting WWVB for
 instance.
 
  Cheers,
  Magnus


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[time-nuts] Oh dear

[Jim Palfreyman]

http://www.ebay.com.au/itm/Antelope-Audio-Isochrone-10M-Rubidium-Atomic-Clock-/270809581736?pt=LH_DefaultDomain_0hash=item3f0d8248a8

Make sure you read the description to discover what it's being sold for.

My chuckle for the day.

Jim Palfreyman
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[time-nuts] Best reason

[Jim Palfreyman]

So when a member of the general public says:

Why do we need really accurate clocks?

What is your answer?

Personally I explain that accurate clocks enable you to pack a higher data
rate into your smart phone. They like that.

Any other thoughts?

Jim
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Re: [time-nuts] Pulsar Source?

[Jim Palfreyman]

Folks, I'm currently writing my thesis on pulsars, but I need to spend time
on it rather than here. :-) But since a lot of this discussion is right at
the front of my brain, here's a summary.

Some pulsars glitch or speed up. The Vela pulsar (PSR J0835-4510) does
this (this is the pulsar I've been studying) and yes these type of pulsars
are bad clocks. A jump of its pulse rate of the order of 10^-6 s/s randomly
every few years is not good. It does nearly settle back to its original
rate after a few months.

The nature of these glitches (in Vela at least) is not well understood, but
three theories have been put forward:

   - An orbiting planet - but this has been discarded due to their
   irregularity.
   - Star quakes caused by a separation of the crust on the surface of the
   neutron star from its super-fluid interior. (Not very popular any more)
   - The effects of tiny micro vortices in the internal super-fluid. (If
   you can understand this paper - good luck to you!)

Now faster pulsars, in particular millisecond pulsars (~700 Hz from memory
is the fastest) are quite good clocks and they do rival atomic clocks. The
hunt is on to find as many of these as they can, well spread across the
sky, so they can look at the effects of gravitational waves on the beams of
these super accurate clocks. This is one proposed method to detect
gravitational waves.

The main problem I see from the original suggestion is that most pulsars
are quite faint and you need a very decent telescope to see individual
pulses. Vela is very bright, and the 26m telescope I used can only just see
the average pulse. I'm studying bright pulses and we can see those easily.

So to dedicate a massive radio telescope (or two) pointing at a millisecond
pulsar just so we can re-transmit it, is probably not sensible. However,
studies of these remarkable pulsars is ongoing.


Jim



On 29 March 2012 10:20, Hal Murray hmur...@megapathdsl.net wrote:


  All that is of course correct. But ultimately the pulsars are a better
  source, I see it as an application question, could it be utilized?
 Perhaps
  building an algorithm and basing corrections on multiple pulsars x-ray
  pulses like a GPS constellation for the next generation of conventional
 GPS.

 I think modern atomic clocks are better than Pulsars.

 Unfortunately, I don't have a good reference handy.  I think the theorists
 have several ideas for why the period of Pulsars change.


 --
 These are my opinions, not necessarily my employer's.  I hate spam.




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Re: [time-nuts] Neutrinos not so fast? (defectove connector)

[Jim Palfreyman]

Maybe the loose connector meant the clock at one end *never* synced with
the GPS and just happened to be 60ns fast. Tighten the connecter, clock
resyncs, problem solved.

Jim


On 23 February 2012 09:57, Rick Karlquist rich...@karlquist.com wrote:

 Maybe they checked the connector by replacing the whole
 fiber optic cable with a new one, and while doing that
 had the oh sh.. moment of realizing the length of the
 old one was 20 meters different than it was supposed to be.
 I think this sort of thing has happened to all of us
 with significant experience.  Or maybe the cable was marked
 with an incorrect length (not due to error by the experimenters)
 and they forgot trust but verify.  We've probably all
 gotten bit by that one as well.

 Rick


 Poul-Henning Kamp wrote:
  In message 9a458dba-3875-43b2-8383-5ca2f86be...@leapsecond.com, Tom
 Van
  Baak
   (lab) writes:
 
 Could be on the electrical side of the adapter, not the optical
 side. It's not impossible to get 60 ns of phase or trigger error
 with RF connectors.
 
  I don't buy that explanation.
 
  It's very hard to get 60 ns *consistent* phase or trigger error,
  with any kind of connector, almost no matter how you go about it.
 
  20m of extra fiber sounds *much* more plausible.
 
  Inventing an excuse about a loose connector to cover up the mistake
  sounds even more plausible.
 
  You really don't want to defend your phd dissertation, being known
  as the idiot who made a fool of both CERN and SanGrasso in one go.
 
  --
  Poul-Henning Kamp   | UNIX since Zilog Zeus 3.20
  p...@freebsd.org | TCP/IP since RFC 956
  FreeBSD committer   | BSD since 4.3-tahoe
  Never attribute to malice what can adequately be explained by
  incompetence.
 
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Re: [time-nuts] GPS fade out, Sat/Sun

[Jim Palfreyman]

Lightsquared doing their final test run...

Jim
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Re: [time-nuts] telling time without a clock

[Jim Palfreyman]

As a reasonably experienced occultation observer (and the very reason I got
into being a time-nut - so I could time these observations), the main
problem is that the number of binocular-observable occultations is actually
quite rare. When the star appears or disappears behind the bright limb it
is actually hard to see - even if the star is very bright. When the moon is
nearly full, even disappearances behind the dark limb are hard.

So ideally you want bright star disappearences on a dark limb with a moon
before first quarter. (Last quarter as well - but then it's a reappearance
and you don't quite know where to look).

This limits the number of bright stars quite drastically. And then you have
clouds...

Jim

On 27 January 2012 07:11, Jim Lux jim...@earthlink.net wrote:

 On 1/26/12 10:14 AM, Chris Albertson wrote:

 On Wed, Jan 25, 2012 at 8:38 PM, Jim Luxjim...@earthlink.net  wrote:

 OK.. without getting into celestial navigation, the whole thing of
 telling
 time with the moon is intriguing.  And with some forethought and data
 available today, we could fairly easily do what folks back in the 18th
 century could not.

 Let's say you run a suitable celestial model and identify all the
 reasonably
 bright and identifiable star that the moon occults in a given day.  The
 moon
 moves about 1/2-1 degree per hour against the star field, so the question
 is, could you find, say, a star every couple hours.


 If you have a telescope and you can measure where it is pointing
 relative to the local meridian, then you don't need the moon.  You can
 use a fine wre in the optical path an watch for when a star crosses
 the wire.  The advantage of this is the telescope does not need a
 tracking motorized mount.  It can be fixed to a concrete pier.Even
 a modest scope in the city can see hundreds of stars per hour.



 I was thinking of something that works anywhere in the world (pretty much)
 with things that you can hold in your hand (the table and your low power
 scope/binoculars).

 In theory, if you knew approximate time (say to a minute or so), then you
 wouldn't even need to find the star.. Look for the moon, the star will be
 right next to the limb, and wait til occultation occurs.





 Using the Moon is only useful if you can't measure where the scope is
 pointed.  The Moon provides a good, well known reference.


 And easy to find in the field.



  So for a

 portable setup it could work best but there is a built-in problem with
 the Moon, you may not have good data on the shape of the limb.
 Mountain ranges and valleys between peaks are different depending on
 your location on Earth.  If you move even a mile your star might hit a
 different place.In fact people have used Lunar occulations to map
 the height of lunar mountains.Another effect is diffraction.  The
 stars don't just wink out because they do have a finite diameter
 People have actually used the moon to measure the diameter of stars by
 accuratly measuring the defraction effects.   But the project had
 problem because of large boulders and mountains on the moon made it
 hard to know the orientation of the knife edge and worse, this would
 chane if you move just a few feet, some different boulder might be
 there.


 This is a very good point.. what sort of effect are we talking about. The
 moon subtends roughly 1/2 degree, 30 min of arc.  What fraction of the
 lunar diameter are these mountains?  Say, 10km high out of 3400 km
 diameter, so one part in 340, or roughly 1/10th minute of arc

 1 degree = 4 minutes of time, so 1 minute of arc is 4 seconds of time.

 Those hills and rocks are on the order of the 1 second time measurement
 uncertainty.




  Another idea that maybe is even better is to use radio observations
 with two antenna that have a very long east/west baseline.   You watch
 the difference in phase to a distant radio source.   As the phase
 different passes zero you know it just went overhead and then the time
 would have to equal the R.A. of the radio source.   Problem is the
 physical length of the cables you'd need to lay out and the lack of
 really bright radio sources.   In theory one could get arbitrary time
 accuracy this way.A few radio source are easy to detect with
 affordable surplus/ebay equipment.



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Re: [time-nuts] telling time without a clock

[Jim Palfreyman]

Download Occult4 by Dave Herald. You can list off all Lunar Occultations
for your location and choose a minimum magnitude to show. Start at 3.0, but
probably 2.0 or above is a binocular viewing - depending on your skies.

Note that Occult4 is an extensive piece of astronomical software for the
experienced amateur. It can do a *lot*. So be prepared to be patient with
it - however once mastered it is very very useful for accurate timing of
astronomical events.

The hardest and yet most satisfying for astronomical time nuts are
asteroidal occultations. This is where a faint asteroid passes in front of
a star and blocks it out for a few seconds. Hard to accurately predict and
hard to observe. It took me 40 attempts over 30 years to see my first.

But when a bunch of amateur astronomers observe and accurately time the
same event you can build up a profile of the shape of the asteroid.

It is a fun but dark path to go down...

Jim


On 27 January 2012 11:35, Jim Lux jim...@earthlink.net wrote:

 On 1/26/12 2:55 PM, Jim Palfreyman wrote:

 As a reasonably experienced occultation observer (and the very reason I
 got
 into being a time-nut - so I could time these observations), the main
 problem is that the number of binocular-observable occultations is
 actually
 quite rare. When the star appears or disappears behind the bright limb it
 is actually hard to see - even if the star is very bright. When the moon
 is
 nearly full, even disappearances behind the dark limb are hard.


 Yes, that's what I observed when I was trying it a while ago..



 So ideally you want bright star disappearences on a dark limb with a moon
 before first quarter. (Last quarter as well - but then it's a reappearance
 and you don't quite know where to look).


 that would sort of limit you to 1 week out of 4. But better than nothing,
 for a technique that requires no outside assistance.



 This limits the number of bright stars quite drastically. And then you
 have
 clouds...


 Yeah, that is something I don't have a feel for.. How many stars are
 candidates? I assume you could get a moon RA/declination list, and then run
 that against the star list.

  This is one of those things that  I was hoping there's probably someone
 who has a program that can do the search trivially.

 I have a moon ephemeris, but I haven't found a convenient star catalog
 (something in ASCII that has ID, RA, Dec, Mag would be nice)




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[time-nuts] Leap second

[Jim Palfreyman]

Leap second has been announced for July.

Jim
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[time-nuts] US New Year countdown - accurate?

[Jim Palfreyman]

Hi folks,

Ignoring the travesty of a lyric change on John Lennon's classic song, did
anyone check to see if the clock countdown in Times Square was actually
accurate?

In times gone past countdowns have been notoriously off (worst I saw was a
tv personality using his own watch and it was 25 seconds out).

Oh and why we're at it here is my worst time-nut story...

Pulled up in a Loading Zone 8-6pm at 18:00:10. Got out, came back 4
minutes later to find a parking officer giving me a ticket.

Me: Look at the time (showing my watch) - it's 6:04

Him: Not by my watch (which said 5:59 at that point).

Me (massive sarcasm voice): So. Let me get this straight. Despite
worldwide time standards keeping clocks accurate to billionths of a second
and costing millions of dollars, all that is now been binned and we now
keep world official time by your watch. Is that right?.

Him: Bu...

Me (interrupting and pulling out mobile): Let's listen to the national
time standard shall we? (I dial and put on speaker - his watch is a good
solid 5 minutes slow).

Him: Walks off screwing up ticket.

The sheer arrogance of the Not by my watch comment irks me to this day.

Jim
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Re: [time-nuts] US New Year countdown - accurate?

[Jim Palfreyman]

A long shot, but was any time-nut actually in the square?

On Monday, 2 January 2012, David davidwh...@gmail.com wrote:
 This sounds like a perfect application for applying antenna wax to
 coaxial cable.

 On Sun, 1 Jan 2012 22:33:00 -0700 (GMT-07:00), Richard W. Solomon
 w1...@earthlink.net wrote:

You can't even get two TV's in the same house in sync with Dish Network !!

The smaller TV in the kitchen gets the feed about a second before the big
set in the living room !! Must be all that delay in the cheap coax they
use !!

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Re: [time-nuts] Slightly OT -- Terminal Strip Covers?

[Jim Palfreyman]

I only know about the ones Don showed. What are the other ones people are
talking about?

On Thursday, 29 December 2011, Don Latham d...@montana.com wrote:

 They're here:


http://www.allelectronics.com/make-a-store/item/TB-35/35A-12-POSITION-TERMINAL-BLOCK/1.html

 Don Latham
 I use european style terminal strips-all electronics or MPJA, I don't
 remember- not expensive at all and completely covered...
 Don

 Steve .
 When terminal strips don't have snap on safety guards I remove half
 the
 mounting screws and replace with nylon standoffs, (most strips i use
 have
 four screw mounts, keep two metals screws for mechanical stability,
 the
 other two are nylon stand off.. Obviously you want a metal screw on
 either
 side, just as with the nylon standoffs)

 Then i cut a piece of plexiglass to length and width then fasten above
 the
 screw terminals.

 I prefer this method over the snap on covers but if a strip already
 has
 the
 cover I'm probably not going to run the extra mile and make my own.

 Steve

 On Wed, Dec 28, 2011 at 8:40 PM, Frederick Bray
 fwb...@mminternet.comwrote:

 This is slightly OT, but what are people using to protect the line
 inputs
 on barrier terminal strips on power supplies often used to power
 Thunderbolts and FE-5680A's?

 On things like the Mean Well and similar supplies the AC line
 terminals
 are not fully enclosed.  I happened to have an enclosure that fit one
 supply, but I have a couple others that I don't have enclosures for.
 I
 would feel a lot more comfortable knowing that it wasn't possible to
 come
 in contact with these terminals accidentally.

 Thanks for any suggestions.

 Fred Bray
 W6WAW

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 --
 Neither the voice of authority nor the weight of reason and argument
 are as significant as experiment, for thence comes quiet to the mind.
 R. Bacon
 If you don't know what it is, don't poke it.
 Ghost in the Shell


 Dr. Don Latham AJ7LL
 Six Mile Systems LLP
 17850 Six Mile Road
 POB 134
 Huson, MT, 59846
 VOX 406-626-4304
 www.lightningforensics.com
 www.sixmilesystems.com



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 --
 Neither the voice of authority nor the weight of reason and argument
 are as significant as experiment, for thence comes quiet to the mind.
 R. Bacon
 If you don't know what it is, don't poke it.
 Ghost in the Shell


 Dr. Don Latham AJ7LL
 Six Mile Systems LLP
 17850 Six Mile Road
 POB 134
 Huson, MT, 59846
 VOX 406-626-4304
 www.lightningforensics.com
 www.sixmilesystems.com



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Re: [time-nuts] Slightly OT -- Terminal Strip Covers?

[Jim Palfreyman]

Ok, yep I've seen those around. Just hate them. Use the ones Don showed.
They are great.

On Thursday, 29 December 2011, Peter Bell bell.pe...@gmail.com wrote:
 Since I happened to have one of those MeanWell PSUs sitting here, this
 is what the terminal strips look like.

 Regards,

 Pete



 On Thu, Dec 29, 2011 at 1:47 PM, Steve . iteratio...@gmail.com wrote:
 Jim,

 I assume something like this:

http://www.allelectronics.com/make-a-store/item/TS-210/10-POSITION-DUAL-ROW-STRIP-20-AMP/1.html

 These tend to be very common in heavier duty applications in the USA,
 though DIN mount terminals are always very common in industrial
 applications.
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Re: [time-nuts] New precision watch

[Jim Palfreyman]

Why don't they build a watch that measures the temperature and every time
you accurately set it, it adds to a small database of time change v
temperature and then adjusts itself internally.

Over time it would become quite accurate I would think.

Jim


On 20 December 2011 11:12, Chuck Harris cfhar...@erols.com wrote:

 Looking at the datasheet for the DS3232, it doesn't appear
 that they mean for it to run off of a small coin cell in a
 watch.  Its battery operating capability is purely to keep
 it running when the main power is turned off.

 I would suspect that the DS3232's power consumption is due
 to its being able to drive sizable loads on its various pins.

 There is nothing inherent in temperature correcting a clock
 that should take significantly more power than would be used
 in a normal watch chip.  Measuring the temperature would be
 the most power hungry operation, I would suspect... but
 fortunately that doesn't have to be done all that often,
 perhaps once per minute.

 After the temperature is measured, a lookup table can be used
 to find a second by second correction value to be added to
 the seconds counter.

 -Chuck Harris


 Dan Rae wrote:

 On 12/19/2011 5:34 AM, Chuck Harris wrote:



 It is not clear to me that a 32KHz xtal is any less stable
 than a 262KHz xtal, though. I would think there would be a lot
 more to be gained by using a microprocessor/thermistor to
 measure the temperature within the watch, and provide an
 adjustment to compensate for the xtal's natural temperature
 sensitivity.

  Chuck, I have recently made a couple of Real Time Clocks for my
 homebrew radios using
 the Maxim DS3232 IC which has a built in TCXO at 32+ kHz doing what you
 describe, the
 temperature is checked at intervals and the corrections applied. The
 performance is
 excellent, once set, getting to what I term Harrison Level, i.e. less
 than a second
 a week error. The downside is that the standby battery demand is pretty
 high and my
 first builds using a Lithium button cell ran for only around a month max,
 so I had to
 go over to NiMH rechargeables. I suspect using this technology in a watch
 one would
 have the same problem.

 The best crystals for room temperature use are around 4 MHz with
 temperature
 inflections around 20C, and this is what was used in an early Braun alarm
 clock I had
 which also had this kind of performance. Long gone, alas.

 Dan



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Re: [time-nuts] The GPS navigation is the weakest point,

[Jim Palfreyman]

Fascinating.

I can picture setting up a bunch of transmitters in the hills to send out
strong GPS-like signals to mimic the real thing. I suppose you could
control those signals to fool the device it is somewhere else. That bit is
very clever - you'd have to adjust the signals taking into account current
positions of all current satellites. Smart bit of work there.

But it would also need incredible timing. Even a few ns out and it wouldn't
work. So how do you set up fantastic timing at different locations of
transmitters throughout a country. Well you've blocked the GPS - so that's
no good.

It would require local atomic clocks (good ones) at each location.

Do they have access to such things? Maybe I'm being naive.

Jim


On 16 December 2011 08:10, J. Forster j...@quikus.com wrote:

 Iran hijacked US drone, claims Iranian engineer  Tells Christian Science
 Monitor that CIA's spy aircraft was 'spoofed' into landing in enemy
 territory instead of its home base in Afghanistan
 Iran guided the CIA's lost stealth drone to an intact landing inside
 hostile territory by exploiting a navigational weakness long-known to the
 US military, according to an Iranian engineer now working on the captured
 drone's systems inside Iran.

 Iranian electronic warfare specialists were able to cut off communications
 links of the American bat-wing RQ-170 Sentinel, says the engineer, who
 works for one of many Iranian military and civilian teams currently trying
 to unravel the drone’s stealth and intelligence secrets, and who could not
 be named for his safety.

 Using knowledge gleaned from previous downed American drones and a
 technique proudly claimed by Iranian commanders in September, the Iranian
 specialists then reconfigured the drone's GPS coordinates to make it land
 in Iran at what the drone thought was its actual home base in Afghanistan.

 The GPS navigation is the weakest point, the Iranian engineer told the
 Monitor, giving the most detailed description yet published of Iran's
 electronic ambush of the highly classified US drone. By putting noise
 [jamming] on the communications, you force the bird into autopilot. This is
 where the bird loses its brain.

 The “spoofing” technique that the Iranians used – which took into account
 precise landing altitudes, as well as latitudinal and longitudinal data –
 made the drone “land on its own where we wanted it to, without having to
 crack the remote-control signals and communications” from the US control
 center, says the engineer.

 The revelations about Iran's apparent electronic prowess come as the US,
 Israel, and some European nations appear to be engaged in an ever-widening
 covert war with Iran, which has seen assassinations of Iranian nuclear
 scientists, explosions at Iran's missile and industrial facilities, and the
 Stuxnet computer virus that set back Iran’s nuclear program.

 Now this engineer’s account of how Iran took over one of America’s most
 sophisticated drones suggests Tehran has found a way to hit back. The
 techniques were developed from reverse-engineering several less
 sophisticated American drones captured or shot down in recent years, the
 engineer says, and by taking advantage of weak, easily manipulated GPS
 signals, which calculate location and speed from multiple satellites.
 Rock Center: Iran's growing influence in
 Iraq
 http://rockcenter.msnbc.msn.com/_news/2011/12/13/9398341-a-growing-iranian-threat-in-wake-of-us-military-withdrawal-from-iraq-this-month
 

 Western military experts and a number of published papers on GPS spoofing
 indicate that the scenario described by the Iranian engineer is plausible.

 Even modern combat-grade GPS [is] very susceptible” to manipulation, says
 former US Navy electronic warfare specialist Robert Densmore, adding that
 it is “certainly possible” to recalibrate the GPS on a drone so that it
 flies on a different course. “I wouldn't say it's easy, but the technology
 is there.”

 In 2009, Iran-backed Shiite militants in Iraq were found to have downloaded
 live, unencrypted video streams from American Predator drones with
 inexpensive, off-the-shelf software. But Iran’s apparent ability now to
 actually take control of a drone is far more significant.

 Iran asserted its ability to do this in September, as pressure mounted over
 its nuclear program.

 Gen. Moharam Gholizadeh, the deputy for electronic warfare at the air
 defense headquarters of the Islamic Revolutionary Guard Corps (IRGC),
 described to Fars News how Iran could alter the path of a GPS-guided
 missile – a tactic more easily applied to a slower-moving drone.

 *Downed US drone: How Iran caught the
 'beast'*
 http://www.csmonitor.com/World/Middle-East/2011/1209/Downed-US-drone-How-Iran-caught-the-beast
 

 “We have a project on hand that is one step ahead of jamming, meaning
 ‘deception’ of the aggressive systems,” said Gholizadeh, such that “we can
 define our own desired information for it so the path of the missile would
 change to 

Re: [time-nuts] gravity controlled pendulumn clock?

[Jim Palfreyman]

Paul, a cricket pitch is 20 m. Sure when the curator draws the lines it is
12cm longer, (and I guarantee s/he uses a metric measure) but when we pace
it out for backyard cricket - its 20 m.

Also my American friends, all your imperial measurements are DEFINED in
terms of metric. eg your inch is 25.4 mm exactly. By definition. It has
been estimated you could save a trillion dollars a year in your economy by
converting - which you will ultimately do. I just hope it is in my
lifetime.

On Wednesday, 14 December 2011, Reeves Paul paul.ree...@uk.thalesgroup.com
wrote:
 Oh dear, what have I helped to get going :-) It has certainly been
 interesting reading! My point was, as Chuck notes, that the metre,
kilogram
 etc. are no more 'precise' than a yard, pound etc. being, essentially,
 arbitrary units and the 'imperial' units can be defined just as accurately
 and in the same way. I will certainly concede that things become
 'interesting' when converting between different units outside of the
 'metric' system (and the 'metric' system went through several versions
-with
 distinctly odd units - before the current standardised one) but that just
 relates to my comment on the reduction of mental arithmetic abilities
 nowadays as against simple decimal point shifting..
 I'm not sure I would agree on being 'forced' to take on certain
measurements
 - we are a lot closer to Europe (sort of...), after all - but pints,
inches
 and miles do seem more 'natural' (a litre is just too much beer) and you
 could never measure a cricket pitch in metres!
 That's all from me,

 Paul Reeves G8GJA



 -Original Message-
 From: Chuck Harris [mailto:cfhar...@erols.com]
 Sent: 14 December 2011 02:05
 To: Discussion of precise time and frequency measurement
 Subject: Re: [time-nuts] gravity controlled pendulumn clock?

 Arnold Tibus wrote:
 I don't understand at all the arguments against the metric system and
 the polemic remarks about. I second the statements of Neville and Jim.

 Without these intelligent french Astronomers like Jean-Baptiste-Joseph
 Delambre, Pierre-François-André Méchain and J.J. Lalande (more infos:
 Ken Alder, The Measure of All Things), we would still have the severe
 problems they had centuries ago!

 Reading WIKIPEDIA, http://en.wikipedia.org
 /wiki/German_units_of_measurement,
 we find a good example of weird units (just for only a part of Germany):

 Before the introduction of the metric system in Germany, almost every
 town had its own definitions of the units shown below, and supposedly
 by 1810, in Baden alone, there were 112 different standards for the
 Elle around Germany. The metric system was a much-needed
 standardisation in Germany.

 This was not only a german problem, and we still have today some
 problems in the world in this area.

 Standardization is fine.  Attempting to force the world's largest economy
to
 bend to the wishes of Europe isn't fine.  The US system has been
 standardized for more than a century, and works very nicely.  Decimal
 inches, decimal pounds, and seconds is every bit as valid a measurement
 system as the equally arbitrary meter, kilogram and second.  Decimal
inches,
 decimal pounds, and seconds flies most of the airframes in the world, won
 WWII, and took mankind to the moon and beyond.

 Saying that the use of pounds, and yards is imprecise is simply ignorant.


 I believe we should think more about what we are saying and doing, so
 we would do a big step forward to become a world community. ...

 Regardless of our measurement systems, we are already a world community.

 The strife we see in the world today is not the result of measurements,
but
 rather is the result of religion, politics, and culture.

 -Chuck Harris

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Re: [time-nuts] gravity controlled pendulumn clock?

[Jim Palfreyman]

John,

No it isn't. Not even close to the world around.

From WP:

One fluid ounce is 1⁄16 of a U.S. pint, 1⁄32 of a U.S. quart, and 1⁄128 of
a U.S. gallon. The fluid ounce derives its name originally from being the
volume of one ounce avoirdupois
http://en.wikipedia.org/wiki/Avoirdupoisof water, but in the U.S. it
is defined as
1⁄128 of a U.S. gallon. Consequently, a fluid ounce of water weighs about
1.041 ounces avoirdupois.

The saying a pint's a pound the world around refers to 16 US fluid ounces
of water weighing approximately (about 4% more than) one pound avoirdupois.
An imperial pint of water weighs a pound and a quarter.


You also have troy and apothecary systems - all different. Urrghhh.


A cubic metre holds 1000 litres (exactly) and a 10x10x10 cm container holds
a litre (exactly). A litre of water weighs 1kg, A ml of water weight 1
gram. (Fantastic for cooking btw - use digital scales, put your bowl on
them, zero it and add, say, 250g of milk/water/most liquids)

And if you want a laugh go youtube American Chopper metric system and
watch that short video. It is the final conclusive proof why metric is
superior.

Jim



On 15 December 2011 07:02, John Ackermann N8UR j...@febo.com wrote:

 On 12/14/2011 2:29 PM, shali...@gmail.com wrote:

  Another small thing I miss is that a liter of water weighs a kg (under
 reference conditions, I forgot what that was :). Then the specific weight
 of various materials only has to be known by their density (ratio of
 specific weight compared to water). It makes all sorts of calculations (
 and guestimations) easy.


 I remember one (and only one) thing from my 7th grade math teacher: A
 pint's a pound the world around.

 John


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Re: [time-nuts] gravity controlled pendulumn clock?

[Jim Palfreyman]

Gentlemen, gentlemen and gentlemen!

We are time-nuts. Accuracy is paramount. We are scientists.

Please steer clear of pounds, feet, cubic yards and other such rubbish.

Scientists speak in metric and so should you.

Please.

Jim


On 13 December 2011 16:24, Don Latham d...@montana.com wrote:



 or you can use a cubic yard of plain sand, about 2700# (depends on how
 moist it is)
 --
 Neither the voice of authority nor the weight of reason and argument
 are as significant as experiment, for thence comes quiet to the mind.
 R. Bacon
 If you don't know what it is, don't poke it.
 Ghost in the Shell


 Dr. Don Latham AJ7LL
 Six Mile Systems LLP
 17850 Six Mile Road
 POB 134
 Huson, MT, 59846
 VOX 406-626-4304
 www.lightningforensics.com
 www.sixmilesystems.com



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Re: [time-nuts] gravity controlled pendulumn clock?

[Jim Palfreyman]

The beautiful irony in all of this, is that the negative statements about
metric and the desire not to change to the metric system comes from the US,
yet it was Benjamin Franklin and Thomas Jefferson who took the original
idea to France when they were ambassadors. The French ran with it and the
US didn't (missing out by only a few votes).

Oh well.

Jim


On 14 December 2011 12:01, Arnold Tibus arnold.ti...@gmx.de wrote:

 I don't understand at all the arguments against the metric system and
 the polemic remarks about. I second the statements of Neville and Jim.

 Without these intelligent french Astronomers like Jean-Baptiste-Joseph
 Delambre, Pierre-François-André Méchain and J.J. Lalande (more infos:
 Ken Alder, The Measure of All Things), we would still have the severe
 problems they had centuries ago!

 Reading WIKIPEDIA, http://en.wikipedia.org
 /wiki/German_units_of_measurement,
 we find a good example of weird units (just for only a part of Germany):

 Before the introduction of the metric system in Germany, almost every
 town had its own definitions of the units shown below, and supposedly by
 1810, in Baden alone, there were 112 different standards for the Elle
 around Germany. The metric system was a much-needed standardisation in
 Germany.

 This was not only a german problem, and we still have today some
 problems in the world in this area.

 I believe we should think more about what we are saying and doing, so we
 would do a big step forward to become a world community. ...

 Sorry for this personal opinion and comments,
 let us come back to timing problems with scientific and technical
 discussions,

 regards,

 Arnold


 Am 14.12.2011 00:15, schrieb Jim Lux:
  On 12/13/11 12:26 PM, shali...@gmail.com wrote:
  Having spent more of my adult life in the US than in France, and
  having been thoroughly exposed to both systems, I can testify (in my
  own name) that it is easier and faster to get a good approximation
  when doing mental arithmetic on engineering problems using the metric
  system than the imperial system.
 
  Of course, when you punch numbers in a calculator, the difference is
  less (even though there are fewer constants involved when using the
  metric system in general) so there is less typing involved.
 
  If you don't care about being accurate, then the imperial system is
  fine :)
  A gallon ( a yard, a pound,...) are not the same depending on where
  you are, and I am not talking about relativistic effects (or maybe I
  am...). Who cares how much is an ounce of water anyhow?
 
  Oh, then you're getting into all sorts of interesting units.  Gallons,
  corn gallons, Scots gallons, etc.
 
  And when speaking of drink, for some amount of time in England, if you
  bought it in a bar, it could only be served and priced in fractions of a
  gill (for distilled spirits) or no less than a pint (for cider, beer,
  etc.) (a pint is, of course, 4 gill (except in Scotland), and since a
  gill is 5 fluid ounces, that makes the pint of beer some 20 ounces).
 
 
  And we are not speaking here of archaic units that haven't been seen in
  centuries.  I think the UK went away from the gill fraction thing in
  bars (I don't recall seeing the sign about all spirits sold in this
  establishment... last winter in Heathrow), but it certainly existed in
  the early to mid 90s.  (There's this weird alcohol unit thing, but I
  have no idea what that is.. probably some quasi metric measure of
  equivalent ethanol).  I think, also, that in Australia, the pint of
  beer varies among states.
 
  And the stone is still used as a measure of human weight (and for
  perhaps other purposes) My wife's English relatives talk about gaining a
  stone over the holidays.  And when hiring a horse to ride in the
  southwest of England, they tend to ask what you weigh in stone (but the
  horse business is the epitome of archaic.. Even in the more modern US we
  run races in furlongs, timing them in 1/5ths of a second, measure height
  of the horse in hands, although we do weigh jockeys in pounds)
 
 
  There are also a whole host of fair weight and measure laws in most
  countries which regulate the minimum sale quantity of something (e.g.
  you cannot buy a loaf of bread weighing less than a pound in the state
  of Oregon, raising an issue if you wish to purchase a demi-baguette).
  Likewise, vegetables and fruit have minimum sale quantities (the odd
  dry pint).  I think in Germany, there's a minimum sale quantity for
  beverages, as well.
 
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Re: [time-nuts] synch for pendulum clock....

[Jim Palfreyman]

I acquired an old pendulum regulator from about the 30's-40's and it had an
electromagnetic coil and a small magnet attached to the pendulum. Some old
electronics passed a constant (but adjustable) current through the coil
either pushing or pulling the pendulum slightly to make its amplitude
bigger or smaller. This enabled you to make slight adjustments in its
period, so you could speed it up or slow it down gently.

I disconnected those electronics and instead passed a small current through
from a digital clock built from a microcontroller and a cheap ebay
rubidium. This current was periodic so it gave the pendulum a very slight
nudge every swing (like pushing a child on a swing).

This worked extremely well and the clock's second hand was spot on (to the
eye) for months.

Then I moved house and the clock was no longer inside but relegated to the
garage where the temperature varies quite a bit (10-30 depending on time of
year). The temperature variations overpowered the slight nudges and it no
longer keeps good time.

I'm seriously toying with the idea of putting a small heater in the
cabinet, so I can have an OCPO - oven controlled pendulum oscillator.

:-)


On 12 December 2011 09:13, Don Latham d...@montana.com wrote:

 Try:
 http://www.bmumford.com/clocks/hj/hj0199.html
 and similar stuff found by googling driving pendulum clock
 Lots of food for thought. Mumford has put some thought into it.
 A lot depends on why you want to drive the thing; e.g. measuring
 perturbations in the gravitational field, a sensitive barometer,
 temperature sensor, etc. etc.
 Don

 Brian, WA1ZMS
  This was talked about several years ago, but did anyone get a fully
  functional design running using electromagnets to synch at one or both
  ends of the travel?
 
  In the meantime I am using a sensor to measure the time period of the
  pendulum for this particular new grandmother wall clock and from that, I
  can synthesize a pulse train from one of the 10MHz lab clocks to drive
  the electromagnets to cause a subtle synch at the end(s) of the pendulum
  travel. The pulse train freq is custom for a given clock.
 
  Anyway.. that's my scheme for now.
  Feedback welcome.
 
  -Brian, WA1ZMS
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 --
 Neither the voice of authority nor the weight of reason and argument
 are as significant as experiment, for thence comes quiet to the mind.
 R. Bacon
 If you don't know what it is, don't poke it.
 Ghost in the Shell


 Dr. Don Latham AJ7LL
 Six Mile Systems LLP
 17850 Six Mile Road
 POB 134
 Huson, MT, 59846
 VOX 406-626-4304
 www.lightningforensics.com
 www.sixmilesystems.com



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Re: [time-nuts] looking for data on time code display

[Jim Palfreyman]

Any chance of a photo?

On 12 December 2011 04:26, Bob Camp li...@rtty.us wrote:

 Hi

 Maybe you could call them up and ask for information on the system they
 went with….:)…

 Sounds like a great way to wind up on a no fly list.

 Bob


 On Dec 11, 2011, at 11:40 AM, Jean-Louis Noel wrote:

  Hi,
 
  From: Steve Byan steveb...@verizon.net
 
  NSN 6625003684180
 
  ==
  NSN: 6625-00-368-4180
  INDICATOR, DIGITAL D
  Part No: 0N194800
  Price Range: n/a
  Delivery Range: n/a
  Mfr/OEM/Agencies: JOINT ELECTRONICS TYPE DESIGNATION SYSTEM, NATIONAL
 SECURITY AGENCY
  ==
 
  Bye,
  Jean-Louis
 
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[time-nuts] FTL neutrinos and the best abstract eva!

[Jim Palfreyman]

Folks,

Since our neutrino friends are close to our hearts, check the abstract of
this paper out:

http://arxiv.org/ftp/arxiv/papers/1110/1110.2832.pdf

Regards,

Jim Palfreyman
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Re: [time-nuts] Those pesky Neutrinos again...

[Jim Palfreyman]

Neville,

If they haven't thought of that one I'd be very very disappointed.

Jim


On Monday, 21 November 2011, Neville Michie namic...@gmail.com wrote:

 Has anyone thought about the fact that verticals converge towards the
centre of the earth?
 The surface distance is greater than the distance at a depth.
 A map distance is made less, a few hundred metres underground.
 Just another thought,
 Cheers, Neville Michie

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[time-nuts] iPhone keeping better time?

[Jim Palfreyman]

Folks,

Is it my imagination or is the iPhone under IOS 5 keeping way better time?

I assume it's contacting the mobile towers more often for reading time.

Jim Palfreymam
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[time-nuts] Speedy neutrino puzzle solved

[Jim Palfreyman]

http://nbcu.mo2do.net/s/18488/29?itemId=tag:dvice.com,2011://3.83661fullPageURL=/archives/2011/10/speedy-neutrino.php

Comments please!
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Re: [time-nuts] Fast than light neutrino

[Jim Palfreyman]

Well that's good Javier - at least we know the timing's good.

Who?

On Friday, 23 September 2011, Javier Herrero jherr...@hvsistemas.es wrote:
 Interesting... one co-author, at least, is member of this list :)

 Regards,

 Javier

 El 23/09/2011 06:51, Jim Palfreyman escribió:

 For those of you who may be interested, here's the paper.

 http://arxiv.org/ftp/arxiv/papers/1109/1109.4897.pdf 
http://arxiv.org/ftp/arxiv/papers/1109/1109.4897.pdf
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[time-nuts] Fast than light neutrino

[Jim Palfreyman]

For those of you who may be interested, here's the paper.

http://arxiv.org/ftp/arxiv/papers/1109/1109.4897.pdf
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Re: [time-nuts] Pulse width for start signal for HP5370

[Jim Palfreyman]

Paul,

Is your trigger set at x10 or x1? If x10 that would narrow your range quite
a bit.

Apart from the oscilloscope suggestions above, make sure your 1PPS is
terminated appropriately. If you don't have 50R termination and it is
required you will get a lot of ringing on the upstroke of the 1PPS and that
can cause problems too.

Jim Palfreyman


On 4 September 2011 18:19, Magnus Danielson mag...@rubidium.dyndns.orgwrote:

 On 04/09/11 09:07, Tom Van Baak wrote:

 Paul,

 Do you have an oscilloscope handy? When doing precision
 time interval measurements it's useful to take a look at what
 the counter inputs actually look like. Use a BNC tee and a 1M
 scope probe (so as not to artificially load the counter input).


 I tend to do the same. Also, some errors is not due to the wrong frequency
 but due to interference, and you can't see that very good with a counter,
 but on a scope.

 Here a short-hand of observations and probable causes:

 1. too high frequency (unstable)

 May be trigger error, usually bad slew-rate on the slope or slope of other
 direction. In really bad cases double frequency can be seen.
 Injected noise has also been seen.

 2. too low frequency (unstable)

 May be trigger error, usually a trigger on the bad slew-rate peak, so
 moving tricker back to safe ground high slew-rate is needed.

 3. unstable

 Beyond the above cases, you can also have ringings or other similar
 features of the signal which can cause bad timing triggers etc. High
 slew-rate is where you want to trigg, if you just can avoid other trigger
 problems.

 Low-pass filters can help to clean up trigging.

 It is a good exercise to train the trigging skills on oscilloscope, since
 you will get fuzzy and/or double/tripple/whatever images.

 So, in all these a good scope gives you clarity and a good feel for the
 signal.


  For pulse inputs it should help you set the DC trigger level
 appropriately. I usually use 0.5 or 1 or 2.5 VDC. But seeing
 the actual waveform helps me decide.

 For CW inputs you will probably want to set the counter to
 AC coupling and zero volt trigger.

 Some counters give you a choice of 50R or 1M termination.
 Be careful with that. In some cases the waveform is much
 cleaner with 50R. In other cases 50R puts way too much
 load on the source and you trigger level or risetime suffers.


 All of the above matches my experience.

 Doing measurements properly is an art. While I am sloppy, it is mostly from
 lazyness. I can even get called in to the lab just to find the signal with
 the scope they already hooked up (usually they made the error of going for
 higher frequency rather than lower frequency offending signals... so that I
 find within minutes with just turning time-base and tuning trigger).

 Also, if you have it, at some times a spectrum analyzer can help you to
 understand what happens... such as unexpected harmonics. The spectrum
 analyzer has better dynamics than the scope.

 Cheers,
 Magnus


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Re: [time-nuts] The future of UTC

[Jim Palfreyman]

Mr HeathKid,

What is your reason for hating dst. The changeover is a pain - but after
that, what is the problem?

Jim


On 22 July 2011 14:23, Heathkid heath...@heathkid.com wrote:

 I live at 39° 57' 46 N and I absolutely HATE DST!  Yes, Indiana... we
 haven't had DST for too long.  It's bad and I hope some day we go back to
 not having it.


 - Original Message - From: Rob Kimberley 
 r...@timing-consultants.com
 To: 'Discussion of precise time and frequency measurement' 
 time-nuts@febo.com
 Sent: Tuesday, July 19, 2011 1:57 PM

 Subject: Re: [time-nuts] The future of UTC


  My earlier reply about flexible working practices still holds. Why not
 just
 move with the seasons. Before clocks, I'm sure that's what we did - we got
 up when it was light, and went to bed when it was dark. The bit in between
 just happens to be elastic...

 I live at 53 degrees North in the UK by the way.

 Rob K

 -Original Message-
 From: time-nuts-boun...@febo.com 
 [mailto:time-nuts-bounces@**febo.comtime-nuts-boun...@febo.com]
 On
 Behalf Of Jim Palfreyman
 Sent: 19 July 2011 1:58 PM
 To: Discussion of precise time and frequency measurement
 Subject: Re: [time-nuts] The future of UTC

 Far out. I've just read so many logical fallacies and government
 conspiracies I'm embarrassed for this high quality list. Let's inject some
 facts here.

 I live at 43 degrees south. At the winter solstice (June 21) the sun rises
 at 7:41 and sets at 16:43.

 At the summer solstice (December 21) the sun rises (no DST) at 04:28 and
 sets at 19:49.

 Sunrise at 04:28 is ridiculous. Including twilight it starts getting light
 at 3:30. Switch to DST and sunrise moves to 05:28 and sets at 20:49. Much
 more reasonable. Nice summer evenings too.

 We have DST for 6 months of the year and wouldn't swap it for anything.

 I understand it's different the closer to the equator you are, but for mid
 latitudes it really works.

 Jim




 On Tuesday, 19 July 2011, Thomas A Frank ka2...@cox.net wrote:

 BLOCK: This may be kind of an urban legend, but I thought I had heard

 that one of the backers behind extending Daylight Saving Time into the
 beginning of November was the candy industry, and it all had to do with
 Halloween.


 Mr. DOWNING: This is no kind of legend. This is the truth. For 25
 years,

 candy-makers have wanted to get trick-or-treat covered by Daylight
 Saving,
 figuring that if children have an extra hour of daylight, they'll collect
 more candy. In fact, they went so far during the 1985 hearings on Daylight
 Saving as to put candy pumpkins on the seat of every senator, hoping to
 win
 a little favor.



 I would say it backfired.

 At least here in Rhode Island, the extra daylight resulted in the

 compression of the trick or treating schedule, since all the little
 goblins
 and ghouls wanted to go out after dark (to better scare the homeowners and
 enjoy their glow in the dark costumes), but they also were expected home
 by
 8pm (local).


 Net result is less candy given out.

 At least that has been my experience.

 Proving you shouldn't tamper with time. Measure yes, tamper, no. :-)

 Tom Frank, KA2CDK



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Re: [time-nuts] The future of UTC

[Jim Palfreyman]

Far out. I've just read so many logical fallacies and government
conspiracies I'm embarrassed for this high quality list. Let's inject
some facts here.

I live at 43 degrees south. At the winter solstice (June 21) the sun
rises at 7:41 and sets at 16:43.

At the summer solstice (December 21) the sun rises (no DST) at 04:28
and sets at 19:49.

Sunrise at 04:28 is ridiculous. Including twilight it starts getting
light at 3:30. Switch to DST and sunrise moves to 05:28 and sets at
20:49. Much more reasonable. Nice summer evenings too.

We have DST for 6 months of the year and wouldn't swap it for anything.

I understand it's different the closer to the equator you are, but for
mid latitudes it really works.

Jim




On Tuesday, 19 July 2011, Thomas A Frank ka2...@cox.net wrote:
 BLOCK: This may be kind of an urban legend, but I thought I had heard that 
 one of the backers behind extending Daylight Saving Time into the beginning 
 of November was the candy industry, and it all had to do with Halloween.

 Mr. DOWNING: This is no kind of legend. This is the truth. For 25 years, 
 candy-makers have wanted to get trick-or-treat covered by Daylight Saving, 
 figuring that if children have an extra hour of daylight, they'll collect 
 more candy. In fact, they went so far during the 1985 hearings on Daylight 
 Saving as to put candy pumpkins on the seat of every senator, hoping to win 
 a little favor.


 I would say it backfired.

 At least here in Rhode Island, the extra daylight resulted in the compression 
 of the trick or treating schedule, since all the little goblins and ghouls 
 wanted to go out after dark (to better scare the homeowners and enjoy their 
 glow in the dark costumes), but they also were expected home by 8pm (local).

 Net result is less candy given out.

 At least that has been my experience.

 Proving you shouldn't tamper with time. Measure yes, tamper, no. :-)

 Tom Frank, KA2CDK



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Re: [time-nuts] The future of UTC

[Jim Palfreyman]

Far out. This discussion is so not time-nuts. I'm going to vent here.
I'll do my best to be polite.

Daylight savings is more beneficial the further from the equator you
go. I love it and would never want it to go. As pointed out, this is a
local issue. Go lobby your local representative.

Metric time?  FFS. The US can't even talk SI with rest of the world
yet - even though their stupid measures are defined in terms of SI -
as they have been for decades. So don't even think about it.

Change the definition of the second?? Just stop right now. Go and
learn what the effects of changing the most accurately measured thing
we have before making silly comments like that!!!

Ok, that's all sorted, let's get to the point on leap seconds. I can
see both sides I really can. Making big changes years in the future is
bad. Remember Y2K?

I don't like the idea of letting DUT1 getting big. But it could be
bigger than it is now without huge issues.

I must admit Poul-Henning's idea of a 20 year advance notice is the
best idea I've heard so far. But I'd recommend 10 years. A good metric
number.

Don't get hung up on noon occurring at 12:00 - the equation of time
blows that right out.

I think stopping leap seconds is bad, and having them regularly is
good for practice - no Y2K problems.

So again, 10 years advance notice is a really nice solution.

/rant

On Saturday, 16 July 2011, Rob Kimberley r...@timing-consultants.com wrote:
 Daylight savings seems to be a bit archaic especially with modern flexible
 working practices. Why not fit the working day around the clock  seasons,
 rather than try to correct things twice a year?

 Rob Kimberley

 -Original Message-
 From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On
 Behalf Of Mark Spencer
 Sent: 15 July 2011 5:51 PM
 To: Discussion of precise time and frequency measurement
 Subject: Re: [time-nuts] The future of UTC

 Sorry for the prior  email with no text.

 If the world could agree on the dates when DST adjustments are applied (if
 individual countries, states etc elect to make DST adjustments) and make any
 needed leap second adjustments at the same time that would be a positive
 step IMHO.



 - Original Message 
 From: Jose Camara camar...@quantacorp.com
 To: Discussion of precise time and frequency measurement
 time-nuts@febo.com
 Sent: Fri, July 15, 2011 9:18:03 AM
 Subject: Re: [time-nuts] The future of UTC

 I think before adding to the fire of UTC1, UTC7 etc. why not just abolish
 this silliness called Daylight Savings Time?  If there is any benefit to it,
 just change business operating hours instead. In summer you work 10 to 6
 instead of 9 to 5 and we don't have to go around the house, car, etc.
 changing clocks. And Congress doesn't have to change the dates the VCRs were
 programmed to do automatically, leaving time for them to take care of
 something more important...

 I used to have pet tortoises that would always ignore DST, looking for their
 food one hour earlier...


 -Original Message-
 From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On
 Behalf Of Steve Rooke
 Sent: Friday, July 15, 2011 8:24 AM
 To: Discussion of precise time and frequency measurement
 Subject: Re: [time-nuts] The future of UTC

 On 16 July 2011 03:14, Poul-Henning Kamp p...@phk.freebsd.dk wrote:
 In message
 CACTjVNynr5Vhrj=e+gfungebpa_u8__26bhjamk2nv6uxgi...@mail.gmail.com
 , Steve Rooke writes:

 Nope, once they have scheduled a leap-second, it happens.

And if it's not needed?

 It is needed, otherwise they would not have scheduled it.

 So, your saying they will predict all the wobbling, drift, internal earth
 changes, etc and do this with any accuracy 20 years in advance, when we have
 already seen significant variations in this.

 If they predict wrong all that happens is that DUT1 wanders a bit more
 around and they will have to catch up with it over the next couple of
 decades.

 Given that straight-jacket, I suggest they schedule one every year then they
 can add and subtract them willy nilly. Yes, New Years Day, worldwide let's
 change the clock regardless. It would make it much more fun for all of us to
 watch what happens. Yes, I'm game for that, great idea.

 Cheers,
 Steve

 --
 Poul-Henning Kamp       | UNIX since Zilog Zeus 3.20 p...@freebsd.org

 | TCP/IP since RFC 956 FreeBSD committer       | BSD since 4.3-tahoe
 Never attribute to malice what can adequately be explained by
 incompetence.

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 --
 Steve Rooke - ZL3TUV  G8KVD
 The only reason for time is so that everything doesn't happen at once.
 - Einstein

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[time-nuts] Primary Time Standards

[Jim Palfreyman]

Hi All,

I've just realised I don't understand something. Something quite basic.

Primary Standards are ones which don't have to be calibrated against others.
My understanding is that Caesium and Hydrogen masers are Primary Standards
(in our field).

Secondary Standards are calibrated against the Primary Standards. My
understanding is that Rubidium is an example of a Secondary Standard.

So I can calibrate my Rubidium clocks by adjusting the C Field. All good.

But why is it that Caesium Clocks and Hydrogen Masers have an adjustment
facility?

And what about the clocks used to determine UTC around the world? Do they
have an adjustment facility? What are they adjusted to? Wouldn't that make
them Secondary Standards?

Now I'm aware that the average of those clocks is UTC, so are those clocks
adjusted regularly to get closer to that average?

I'm sure someone can clear this up for me.

Regards,

Jim
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Re: [time-nuts] Personal time keeping...

[Jim Palfreyman]

I have posted about this before, but I actually have one of the
original six speaking clocks used in Australia. I keep it running and
found a way to synchronise it to the gps.

There was one in each state and it provided the message over the phone
as well as accurate time signals to radio stations. Originally it was
all synced back to a caesium unit in Melbourne via phone lines. They
knew the phone line delay because they put an atomic clock on a plane
and flew it to each state on installation.

It's my most treasured possession. I have it connected up to an old
black Bakelite phone for extra ooohhs and aaahhhs.

It's the size of a fridge.

Jim


On Friday, 20 May 2011, Dr. David Kirkby david.kir...@onetel.net wrote:
 On 05/19/11 05:20 PM, Max Robinson wrote:



 Is anyone else old enough to remember when you would hear on the radio
 Time at the tone, 5 o'clock. Beep. The tone was anywhere from half a
 second to one second long and it might have been hard to pin down if the
 beginning or the end of the tone was 5 o'clock but it was probably
 within a couple of seconds accuracy which was plenty good for setting
 your watch or the kitchen clock. Why don't you hear that now a days?
 Digital TV has latency which is dependant on the equipment used by the
 cable or satellite company and is somewhat variable between receiver
 manufacturers. The engineer of our local public radio station told me
 that digital radio has 7 seconds delay. When I asked the station manager
 if there were any plans to run studio time 7 seconds ahead of real time
 so listeners would get accurate time he just frowned.

 Regards.

 Max. K 4 O D S.

 Email: m...@maxsmusicplace.com


 In the UK you can phone the number 123 from a BT phone and get:

 At the third stoke the time from BT will be 10 10 and fixty seconds beep beep 
 beep
 At the third stoke the time from BT will be 10 11 precisely beep beep beep
 At the third stoke the time from BT will be 10 11 and ten seconds beep beep 
 beep

 At one time (excuse the pun), it used to say something like At the third 
 stoke the time sponsored by Accurist will be ...

 Before that, I can't recall, but I think when I was younger there was neither 
 BT or Accurist in the message.


 --
 A: Because it messes up the order in which people normally read text.
 Q: Why is top-posting such a bad thing?
 A: Top-posting.
 Q: What is the most annoying thing in e-mail?

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Re: [time-nuts] Personal time keeping...

[Jim Palfreyman]

This one was taken after The Doctor dropped me off in November this
year. He picked the time and date perfectly, hence the shocked look on
my face.

http://jimpalfreyman.zenfolio.com/p420249340/e444AB1


On Saturday, 21 May 2011, Brooke Clarke bro...@pacific.net wrote:
 Hi Jim:

 How about a photo?

 Have Fun,

 Brooke Clarke
 http://www.PRC68.com


 Jim Palfreyman wrote:

 I have posted about this before, but I actually have one of the
 original six speaking clocks used in Australia. I keep it running and
 found a way to synchronise it to the gps.

 There was one in each state and it provided the message over the phone
 as well as accurate time signals to radio stations. Originally it was
 all synced back to a caesium unit in Melbourne via phone lines. They
 knew the phone line delay because they put an atomic clock on a plane
 and flew it to each state on installation.

 It's my most treasured possession. I have it connected up to an old
 black Bakelite phone for extra ooohhs and aaahhhs.

 It's the size of a fridge.

 Jim


 On Friday, 20 May 2011, Dr. David Kirkbydavid.kir...@onetel.net  wrote:


 On 05/19/11 05:20 PM, Max Robinson wrote:



 Is anyone else old enough to remember when you would hear on the radio
 Time at the tone, 5 o'clock. Beep. The tone was anywhere from half a
 second to one second long and it might have been hard to pin down if the
 beginning or the end of the tone was 5 o'clock but it was probably
 within a couple of seconds accuracy which was plenty good for setting
 your watch or the kitchen clock. Why don't you hear that now a days?
 Digital TV has latency which is dependant on the equipment used by the
 cable or satellite company and is somewhat variable between receiver
 manufacturers. The engineer of our local public radio station told me
 that digital radio has 7 seconds delay. When I asked the station manager
 if there were any plans to run studio time 7 seconds ahead of real time
 so listeners would get accurate time he just frowned.

 Regards.

 Max. K 4 O D S.

 Email: m...@maxsmusicplace.com


 In the UK you can phone the number 123 from a BT phone and get:

 At the third stoke the time from BT will be 10 10 and fixty seconds beep beep 
 beep
 At the third stoke the time from BT will be 10 11 precisely beep beep beep
 At the third stoke the time from BT will be 10 11 and ten seconds beep beep 
 beep

 At one time (excuse the pun), it used to say something like At the third 
 stoke the time sponsored by Accurist will be ...

 Before that, I can't recall, but I think when I was younger there was neither 
 BT or Accurist in the message.


 --
 A: Because it messes up the order in which people normally read text.
 Q: Why is top-posting such a bad thing?
 A: Top-posting.
 Q: What is the most annoying thing in e-mail?

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Re: [time-nuts] Overheard from NASA

[Jim Palfreyman]

Why xray pulsars?

Millisecond pulsars have shown themselves to be very accurate - wouldn't an
ensemble of those be a better choice?

Jim


On 10 May 2011 13:45, Jim Lux jim...@earthlink.net wrote:

 I wasn't intending to cast aspersions...   I was more giving an example of
 somewhere that atomic clocks need more work.   And, I'm pleased that this
 group/list exists..  It's pointed me towards some useful stuff to solve some
 problems with the KaTS, and, as well, the archives are a great resource to
 which to point colleagues for help on Allan dev, etc.

 FWIW, for flight, the hot ticket is going to be Hg ion, if they can ever
 get it qualified...the physics package is pretty well there, but the rest is
 slogging along.

 And if someone figures out how to use xray pulsars in a flight qualified
 way, we'll fall on them with gratitude.

 On May 9, 2011, at 18:37, William H. Fite omni...@gmail.com wrote:

  Jim, keep in mind that that was not my statement but one made to a small
  group of people, including me, over at the Cape.  The guy is a PhD (I
 know,
  I know, I am too, and what does it get me?) senior research scientist at
  NASA whose specialty is metrology.  Now, you may be convinced that he is
 a
  complete idiot but I work with NASA quite often and I can assure you that
  they don't hire idiots as senior research scientists.
 
  I'm a statistician and in no way qualified even to have an opinion on
 this
  topic.  Just thought it might interest the group.
 
  Bill
 
 
 
  On Mon, May 9, 2011 at 8:21 PM, Jim Lux jim...@earthlink.net wrote:
 
  On 5/9/11 8:25 AM, William H. Fite wrote:
 
  Overheard from a senior NASA research metrologist:
 
  The only reason we're doing it is because we *can* (improving clock
  accuracy, said in the context of the aluminum clock).  We can already
 time
  so accurately, just as an example, that if we launched a spacecraft
 today
  toward Sirius we could predict its location when the craft arrived many
  thousands of years from now, to within a thousand miles or so.
 
  That's not a precise quote but it is a close paraphrase.
 
  Heck, I thought that was why time nuts did it, anyway.
 
 
 
  When it comes to good clocks on spacecraft, we're a long way away from
  better than we need, particularly for small power/mass/volume.
 
  Having a atomic clock on board would let you do things like one-way
  ranging, particularly techniques such as delta DOR, which can give you
  cross range measurements (i.e. azimuth).
 
  Knowing the position to 1000s of km may not be particularly useful, even
 at
  long distances, but as a practical matter, we want to know distances to
 cm
  or mm at Jupiter or Saturn distances.
 
  Given that Jupiter is about 600-800E9 meters away (call it a round 1E12
  meters), that's a precision of 1 part in, say, 1E14.
 
  We use precise measurements of range rate (on the order of mm/s) to
  determine the gravity field, and from that the internal structure of a
  planet.  The Juno spacecraft has a coherent transponder that contributes
  Allan deviation of around 1E-15 or 1E-16 over 1000 seconds, with the
 rest of
  the measurement system (transmitter on earth, receiver on earth,
 propagation
  uncertainty at 32/34 GHz) contributing roughly comparable amounts.
 
  The transponder (KaTS) receives a signal at 34 GHz from earth at a
 fairly
  low SNR and generates a carrier at 32 GHz with a fixed ratio of
  phase/frequency to transmit back.  The SNR is limited by the power we
 can
  transmit on Earth (tens of kW, with BIG antenna gain) and the size of
 the
  antenna on Juno.
 
  IF we had a good clock on board, we wouldn't need to worry about the
  transmitter on earth and one way propagation uncertainty for the
  outbound path.
 
  A USO (quartz oscillator in a temperature controlled dewar) isn't in
 this
  class of performance (and is big and power hungry to boot).
 
 
  If you had a good onboard oscillator, you can do VLBI type measurements
 to
  measure not only range, but angle to a higher precision than is
 currently
  possible.
 
 
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Re: [time-nuts] Result of Earth Quake speeds up earth?

[Jim Palfreyman]

No one has commented on my graph. I would have thought that change
would easily be detected.

Jim

On Sunday, March 20, 2011, cook michael michael.c...@sfr.fr wrote:
 Le 20/03/2011 05:59, Bruce Griffiths a écrit :


 jimlux wrote:




 A 10-12m diameter dish is probably close to the minimum feasible aperture.
 A 4m dish can be made to work in conjunction with a mauch larger dish
 (eg 30m).



 The original speculation was for measuring the small change in earth rotation 
 rate, for which some sort of interferometric measurement of a stellar source 
 could be used.


 I sincerely doubt that it will be possible to get undisputed verification of 
 this speed up as the magnitude is swamped by the irregular diurnal and 
 sub-diurnal rotation rates induced by tidal effects that are at lease a 
 magnitude greater and for which the error bars are of the same order or 
 grater than the predicted shift.

 There was a similarly predicted rotation shift predicted for the Chile quake 
 of 28 February 2010 (1,26us). There was IIRC no verification of that AFAIK. 
 Check the tidal effects at

 http://bowie.gsfc.nasa.gov/ggfc/tides/intro.html  for the tidal effect
 and
 http://hpiers.obspm.fr/     for rotational measured speed changes
 http://hpiers.obspm.fr/eop-pc/index.php?index=news    for the statement of 
 detectability.







 The source has to be bright (so you can detect it with a practical antenna.. 
 not everyone has a 30m dish in their back yard)
 The source has to be small angle (or at least something that you could 
 accurately determine the centroid of)
 The source has to be not moving  (which I think leaves out using something 
 like jupiter)
 The frequency of measurement has to be somewhere that the atmosphere won't 
 dominate the uncertainty (leaving out optical, I think)


 SO what's the brightest small angular radio source out there?


 3C273

 RA 12:29.1 DEC 02:03.1




 As someone else has pointed out, measuring the earth surface position 
 relative to spacecraft orbits, e.g. GPS, would be another technique.  In 
 fact, a high resolution measurement of the position of a geosync sat might 
 do.. If the earth's rotation rate changes you'd have to adjust the height of 
 the satellites in Clarke orbit to keep them stationary.

 Unfortunately, for earth orbiters, there's enough other perturbations that 
 you probably can't see it.  They already have to move satellites around to 
 compensate for things like solar wind, air drag (for LEO), etc.

 But maybe for a spacecraft in deep space, between planets, which is on a well 
 understood trajectory?



 Bruce



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Re: [time-nuts] Result of Earth Quake speeds up earth?

[Jim Palfreyman]

Just for fun I plotted the UT1-UTC data from the IERS Bulletin A.
Here's the raw data:

UT1-UTC
s
-0.18115
-0.18232
-0.18353
-0.1847
-0.18576
-0.18674
-0.18763
-0.18842
-0.18912
-0.1897
-0.1903
-0.19103
-0.192
-0.19324

This is from March 4 to Match 17 inclusive.

I don't know if it's a fluke, but the line takes a definite step to
the right before continuing on its merry way.

At a glance x an y graphs seem to show nothing.

Jim Palfreyman

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Re: [time-nuts] Coalition to Save GPS

[Jim Palfreyman]

I find this quite strange. I have three questions:

1) Why would your FCC allow such a thing?

2) For this company to have high bandwidth they're going to need a
precision time source at each transmitter. Will it be gps??? :-)

3) Wouldn't the most used GPS devices in the US be smartphones (iPhone
etc)? Tell those users that location services won't work any more and
wait for a reaction.

Jim


On Sunday, March 13, 2011, Kevin Haywood haywoo...@yahoo.com wrote:
 The opposition to the use of L-band spectrum for broadband Internet access is 
 growing. Several companies and industry organizations have joined the 
 Coalition to Save Our GPS.
  http://www.saveourgps.org/

 A study by Garmin details the effect the Lightsquared transmitters will have 
 a typical consumer-grade GPS receiver.
  http://www.saveourgps.org/studies-reports.aspx

 As a map maker and outdoor enthusiast, I hope this decision is reversed.

 Kevin Haywood






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Re: [time-nuts] Coalition to Save GPS

[Jim Palfreyman]

 (3) If they get their license rest assured that GPS as we know it will
 disintegrate, along with every user of it (civilian and military).  Rest
 assured that a LOT of effort is being spent fighting this.


Are you sure about this??

Imagine the day they power up their transmitters (I know it would be
gradual, but stick with me), GPS stops working in a good portion of the
continental USA. (4 transmitters, 15000W each)

There would be an outcry by the public with all those smartphones suddenly
not working for location services. Not to mention cell phone towers who use
GPS for timing (sure they can fix it - but are those phone companies going
to be happy to spend the extra money?).

And what about the military - they'll have something to say - after all it
was they who wanted GPS to orginally to guide their missiles.

So the outcry would be huge, the new transmitters are shut down so the GPS
is restored - and then the lawsuits begin.

I'm not in America, but are you telling me the government would prefer this
new broadband service in exchange for GPS and (more importantly) everything
that runs off it?

Whatever happens, I'm going to sit back here and enjoy the show!

Jim
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Re: [time-nuts] MiniMac 2816AT

[Jim Palfreyman]

I love the lightweight comment.

It has to weigh 20kg!

On 7 March 2011 19:19, gandal...@aol.com wrote:

 It seems to be an L1/L2 dual frequency surveying receiver.
 Searching for minimac 2816, without the AT, seemed to produce a  few
 more results with the following from 1988 amongst them

 _http://cedb.asce.org/cgi/WWWdisplay.cgi?58399_
 (http://cedb.asce.org/cgi/WWWdisplay.cgi?58399)
 ---

  A new portable dual-frequency Global  Positioning System (GPS) receiver is
 being delivered to customers by Aero  Service. The MINI-MAC Model 2816
 receiver is lightweigt, portable, and designed  for operation by one person
 in
 field environments. The receiver is packaged to  withstand harsh
 environmental conditions and deliver dual-frequency data of the  highest
 quality.
 Decoded broadcast ephemerides allow for field data. Time and  pseudoranges
 obtained via the unit’s coarse/acquisition (C/A) code L1 capability  are
 used to
 obtain precise time synchronization. The receivers record on  canonical
 times,
 so it is not necessary to start different receivers at the same  time in
 order to maintain synchronous phase observations. The MINI-MAC 2816
  Surveyor
 is capable of tracking up to eight satellites simultaneously using C/A
  code
 on L1 and Aero’s proven proprietary codeless methods on L2. An L1-only
 version, Model 1816, is also available. Phase lock can be maintained on up
 to
 eight satellites in kinematic operations. The receiver is designed for
 future  implementation of kinematic software without any required hardware
 changes.  Various aspects of the receiver are discussed and details of a
 number of
 field  results are provided.

 --

 regards

 Nigel
 GM8PZR
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[time-nuts] MiniMac 2816AT

[Jim Palfreyman]

Hi All,

Sorting through my old junk and this beast peaked its head above the pile. I
opened it up not even knowing what it was. Seeing  Antenna, 1PPS and 10
MHz connectors did get me wondering if it was a GPS unit. It's quite large
and heavy. It contains a large (in size!) hard drive and what looks like an
OCXO - not to mention lots of good 80's hardware. And built like a tank.

Not much on the web about this unit.

It does seem it's the equivalent of a giant Thunderbolt.

It needs 115V and so I can't power it up (yet), but I was wondering does
anyone know anything about these beasts or even have a manual of any form?

Regards,

Jim Palfreyman
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Re: [time-nuts] LCD display connector

[Jim Palfreyman]

Folks,

Well I had some 70% isopropyl alcohol swabs and so used them.

No matter what I did there are still some segments not working. Checked the
contacts on the pcb with a cro and all seemed to have some sort of signal on
them. Tried rotating and flipping the zebra strip and always the same
segments not working.

My conclusion is that the LCD is damaged. (Looks fine though.)

May have to buy another unit. :-(

Thanks for the interesting thread.

Jim Palfreyman

On 5 January 2011 13:29, J. L. Trantham jlt...@att.net wrote:

 Drug store?

 Not a name I recognize here in FL.

 Joe

 -Original Message-
 From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On
 Behalf Of Robert LaJeunesse
 Sent: Tuesday, January 04, 2011 6:24 PM
 To: Discussion of precise time and frequency measurement
 Subject: Re: [time-nuts] LCD display connector


 I got my last few 99% pints at Meijer here in Michigan.

 Bob L.



 
 From: J. L. Trantham jlt...@att.net
 To: Discussion of precise time and frequency measurement
 time-nuts@febo.com
 Sent: Tue, January 4, 2011 6:54:43 PM
 Subject: Re: [time-nuts] LCD display connector

 I have found 91% at CVS Pharmacy and 99% from the electronics suppliers.
 Where in a grocery store or drug store can I find 99%?

 Joe

 -Original Message-
 From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On
 Behalf Of Javier Herrero
 Sent: Tuesday, January 04, 2011 9:51 AM
 To: time-nuts@febo.com
 Subject: Re: [time-nuts] LCD display connector


  91% and 99% isopropyl alcohol, available from your drug, or grocery,
  store


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[time-nuts] LCD display connector

[Jim Palfreyman]

Apologies for being a teensy tiny bit OT. But is relevant on the whole.

I have a remote control for an air conditioner whos display is only
partially working.

Upon internal inspection it seems the sticky thingy (technical term)
connecting the LCD display to the board is not attached properly.

Any hints on how to reattach these?

Jim Palfreyman

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Re: [time-nuts] LCD display connector

[Jim Palfreyman]

Hi All,

The item is indeed the zebra strip.

Alignment is pretty good (I think) as the case ensures it.

So it sounds like it might need a clean. I shall look into that one...

Postscript... Just searched the world for DeoxIT and it turns out the local
Australian supplier has a shop 50m from where I work. Yeah!!

Jim


On 4 January 2011 07:58, Robert Atkinson robert8...@yahoo.co.uk wrote:

 Hi,
 There are (at least) two types of connector. Some displays use both types.
 First is Zebra-strip which is an elastomer sandwich of
 conducting/insulating material that conducts vertically but not
 horizontally. These rely on mechanical clamping and are what Gary  is
 referring to. The other is a tape with conductive tracks that is stuck
 down. I think this is what Jim has. These can sometimes be re-attached by
 burnishing with a rounded tool. If they have come completely unstuck  I've
 had some sucess by holding it in place with thin adhesive (Kapton) tape and
 applying pressure with a foam block between the strip and the case. Good
 luck.

 Robert G8RPI.

 --- On Mon, 3/1/11, gary li...@lazygranch.com wrote:


 From: gary li...@lazygranch.com
 Subject: Re: [time-nuts] LCD display connector
 To: Discussion of precise time and frequency measurement 
 time-nuts@febo.com
 Date: Monday, 3 January, 2011, 20:40


 You need to clean the elastomer. I've done this with Caig deoxit, though
 I would search their website to see if they have a special product for
 the task.

 http://store.caig.com/

 Generally the LCD is just pressed against the elastomer, so you may need
 to see that the pressure is sufficient.

 On 1/3/2011 12:34 PM, Jim Palfreyman wrote:
  Apologies for being a teensy tiny bit OT. But is relevant on the whole.
 
  I have a remote control for an air conditioner whos display is only
  partially working.
 
  Upon internal inspection it seems the sticky thingy (technical term)
  connecting the LCD display to the board is not attached properly.
 
  Any hints on how to reattach these?
 
  Jim Palfreyman
 
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Re: [time-nuts] Adjusting accuracy of a Casio G-Shock watch

[Jim Palfreyman]

Hi Brooke,

I've adjusted the watch as best I can within the limitations of the trimmer.
The waveform was drifting 10 microseconds (slow) in about 20 seconds and so
this should come out to 1 second in 23 days.

I have now set the watch accurately and will follow it's progress. I plan to
see how long it takes to be a second out and then re-open the cover and
re-check the wave form.

From that I should be able to work out the relationship between the measured
frequency and actual watch accuracy.

Watch (*cough cough*) this space.

:-)

Jim

P.S. I'm so looking forward to being able to have a genuine atomic watch on
my wrist. Surely it can't be too far away...


On 16 December 2010 06:03, Brooke Clarke bro...@pacific.net wrote:

 Hi Jim:

 It may not be a good idea to adjust the watch so that the frequency is spot
 on at the time the adjustment is made.
 A better idea may be to wear the watch for a week and note the fractional
 time error then adjust the frequency so the offset matches the error.

 Have Fun,

 Brooke Clarke
 http://www.PRC68.com


 Jim Palfreyman wrote:

 Fellow time-nuts.

 Over in another part of the internet is a group of people who love their
 Casio G-Shock watches. These digital watches have been around for decades
 and are built very well.

 The one I own is an atomic and solar model (i.e. no battery
 replacement).
 However being in Tasmania, I cannot receive the low frequency time
 signals.
 When I first received the watch it's accuracy was excellent. Under 10
 seconds a year. I even posted on here about it. Since then though it has
 drifted somewhat.

 After a ton of internet searching on how to open the case and how to
 adjust
 these watches (this is non trivial as the models are all very different
 and
 no instructions existed for this model - the GW-810D) I have finally
 cracked
 it.

 Interestingly, the module has a pad that gives off a stepped square wave
 at
 32768/48 Hz. So with well calibrated equipment (which we all have of
 course)
 it is trivial to adjust the trimmer to put the watch back to decent
 accuracy. Using the smallest adjustment of the trimmer that I could muster
 I
 could get it down to about 0.5 in 10^6 or 1 second in around 20 days. Not
 as
 good as when I got it - but I was probably just lucky.

 Over in mygshock.com they struggle with this sort of timing stuff -
 whereas
 my big deal was opening the case!

 Just posting in this in case anyone here is interesting in adjusting their
 G-Shock.

 Jim
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Re: [time-nuts] Frequency counter recommendation

[Jim Palfreyman]

I asked the same question of this list a number of years back, took a few
different routes and ended up with precisely what has been suggested here:

HP 5370B
Prologix GPIB-USB
And an HP 3325B function generator to round it all out nicely.

Also, if ever asked by the financial controller *why* you bought such a
5370B, a cool demo is to demonstrate the speed of electricity along a
metre or two of cable.

Jim Palfreyman

On 16 December 2010 16:54, Dave M dgmin...@mediacombb.net wrote:

 I've seen several posts that mention the 5370 counter.  Certainly looks
 like a capable instrument.  I'll be on the lookout for one that is in
 reasonably good condition and WORKS.  I downloaded the NIST pub that you
 mentioned, and with the cold days and colder nights, I'll have lots of time
 to ponder it.
 Re: Don Latham's response - I've never seen Robot BASIC, but I'll look it
 up.  I assume that it's a GPIB controller application??
 Re Stan, W1LE's response - Thanks for the Prologix recommendation.  I'll
 look into it.
 And thanks to all the other responders... I really appreciate your taking
 time to offer your advice.

 Dave M


  Hi Dave,

 On 12/15/2010 08:55 PM, Dave M wrote:

 I'm a retired electronics tech and computer programmer.  I have a
 pretty decently equipped shop for almost all of my projects and
 experiments. However, my time and frequency equipment is a bit long
 in the tooth.  I have a couple old HP 5328A counters (commercial
 version; not the military version), one with a 10544, the other with
 a 10811 oscillator.
 I have an HP Z3801A that has been operating well for several years,
 and recently acquired a TBolt to keep the counters in tune.  I also
 have a good distribution amp and  couple of old Montronics (Fluke)
 frequency comparators.
 What I'm looking for now, is a recommendation for a good low-cost
 ($400) counter that will get me on the way to performing some of
 the down in the grass noise, jitter and deviation tests that the
 more learned members of the group discuss.  I know that new
 equipment is far out of my budget, but I'm also aware that some of
 the older, now obsolete (also cheaper) equipment is quite capable of
 doing what I want to do. I prefer HP equipment since manuals are
 much easier to find than most other brands.
 I'd also like recommendation for a good low-cost GPIB controller
 that allows me to write software to control some of my instruments.
 I have experience writing software in BASIC on a Fluke 1722A
 controller.  I've seen these controllers on the Bay and other online
 vendors, but I've not located the BASIC discs for them.  Any advice?
 I realize that a counter is not the only piece that I need, but it's
 first on my list.  Other, more applicable equipment is on my want
 list, but will have to wait for a bit.


 A HP5370A/B and a Prologix USB-GPIB interface seems like a popular
 solution, and it should fit inside your budget more or less. There is
 already software available (from John Miles for instance) that works
 with that solution, but it should also allow yourself some programming
 exercises.

 This will certainly get you started. There are several decades to go
 down into the noise for the really good sources and reducing
 measurement noise. It will be a fairly good solution for many decent
 sources.

 Grab a copy of the NIST SP 1065 and ponder over it.

 Cheers,
 Magnus





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[time-nuts] Adjusting accuracy of a Casio G-Shock watch

[Jim Palfreyman]

Fellow time-nuts.

Over in another part of the internet is a group of people who love their
Casio G-Shock watches. These digital watches have been around for decades
and are built very well.

The one I own is an atomic and solar model (i.e. no battery replacement).
However being in Tasmania, I cannot receive the low frequency time signals.
When I first received the watch it's accuracy was excellent. Under 10
seconds a year. I even posted on here about it. Since then though it has
drifted somewhat.

After a ton of internet searching on how to open the case and how to adjust
these watches (this is non trivial as the models are all very different and
no instructions existed for this model - the GW-810D) I have finally cracked
it.

Interestingly, the module has a pad that gives off a stepped square wave at
32768/48 Hz. So with well calibrated equipment (which we all have of course)
it is trivial to adjust the trimmer to put the watch back to decent
accuracy. Using the smallest adjustment of the trimmer that I could muster I
could get it down to about 0.5 in 10^6 or 1 second in around 20 days. Not as
good as when I got it - but I was probably just lucky.

Over in mygshock.com they struggle with this sort of timing stuff - whereas
my big deal was opening the case!

Just posting in this in case anyone here is interesting in adjusting their
G-Shock.

Jim
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Re: [time-nuts] Adjusting accuracy of a Casio G-Shock watch

[Jim Palfreyman]

Bill,

Indeed undoing the four screws is all that's needed. However on some
models those screws are covered by various plastic bits which are
quite confusing to remove. (Unless you are a gshock-nut!)

Jim

On Wednesday, 15 December 2010, Bill Hawkins b...@iaxs.net wrote:
 Jim,

 I have such a watch, purchased in Singapore in Oct 2009. It is
 solar, but it has no radio connection. It is water-resistant
 to 20 atmospheres (bar). I don't wear it, but I keep it by a
 southern window.

 The back cover appears to be held on by four screws. I've not
 tried to open it. It's off by two hours and 91 seconds, over
 a year. It's possible that I didn't make the final time zone
 adjustment when I got back to Minnesota.

 What was the problem with getting the back off?

 Bill Hawkins


 -Original Message-
 From: Jim Palfreyman
 Sent: Tuesday, December 14, 2010 10:17 PM
 To: Discussion of precise time and frequency measurement
 Subject: [time-nuts] Adjusting accuracy of a Casio G-Shock watch

 Fellow time-nuts.

 Over in another part of the internet is a group of people who love their
 Casio G-Shock watches. These digital watches have been around for decades
 and are built very well.

 The one I own is an atomic and solar model (i.e. no battery replacement).
 However being in Tasmania, I cannot receive the low frequency time signals.
 When I first received the watch it's accuracy was excellent. Under 10
 seconds a year. I even posted on here about it. Since then though it has
 drifted somewhat.

 After a ton of internet searching on how to open the case and how to adjust
 these watches (this is non trivial as the models are all very different and
 no instructions existed for this model - the GW-810D) I have finally cracked
 it.

 Interestingly, the module has a pad that gives off a stepped square wave at
 32768/48 Hz. So with well calibrated equipment (which we all have of course)
 it is trivial to adjust the trimmer to put the watch back to decent
 accuracy. Using the smallest adjustment of the trimmer that I could muster I
 could get it down to about 0.5 in 10^6 or 1 second in around 20 days. Not as
 good as when I got it - but I was probably just lucky.

 Over in mygshock.com they struggle with this sort of timing stuff - whereas
 my big deal was opening the case!

 Just posting in this in case anyone here is interesting in adjusting their
 G-Shock.

 Jim
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Re: [time-nuts] wwvb signal strength

[Jim Palfreyman]

I receive the Japanese low frequency signal here in Tasmania. I get it
on a simple travel clock placed up high on a wooden bookshelf. Still
figuring out which times of the year are best.

Jim

On Sunday, 5 December 2010, Stanley Reynolds stanley_reyno...@yahoo.com wrote:
 Past week wwvb propagation has been very good here in Alabama may be a good 
 time
 to play with some of your wwvb discipline oscillators.

 Winter is, of course, the time of best ground-wave propagation from WWVB, so
 this is about as good as it’s ever going to get. from link :

 http://softsolder.com/2010/01/06/wwvb-reception-quality/

 Stanley

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[time-nuts] Randomly stumbled on this...

[Jim Palfreyman]

http://www.marketwatch.com/story/frequency-electronics-awarded-contract-for-chip-scale-atomic-clock-2010-11-04?reflink=MW_news_stmp
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