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).
I don't think it quite works that way.
Cesium is the primary standard because it's the definition of a second.
Hydrogen
Ok, I have a dds receiver locked to a gpsdo, the radio can only be tuned
in 1
hz increments but should be dead on. I can feed the passband into speclab
via VAC and measure a carrier OTA. No problem there...can get decent
resolution but there is some uncertainty with regard to the dds
I am an extreme novice in this field but my understanding is that the
C-Field adjustments on the CS standards (5061A, 5061B that I am familiar
with) allow for insuring that the appropriate energy state transition of the
CS Ion is chosen as the 'reference' for the standard, something that can be
Hi
I've looked at a random sample of a couple dozen Rb's that are in the 5 to
30 year old range. In about 90% of the cases I'm reasonably certain they
haven't been adjusted since they left the factory. If they still worked,
they all came in at or below +/- 3x10^-9.
Bob
-Original
On 14/07/11 04:26, Jim Palfreyman wrote:
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).
In
It's a shame these, and other elderly scholarly works, can't just be
released for the greater good, without all this red tape tying them
down. I wonder how much better the world would advance if we could all
go back to the days when we shared knowledge and skills freely between
engineers before
I agree, and have worked toward that end, but those who do the scanning
(and file cleanup) sometimes seem to think they acquire ownership of the
documents in that process. This leads to problems. Been there, done that.
-John
==
It's a shame these, and other elderly scholarly
Shame, isn't it, but they deserve something for the effort they put
in. What is needed is the open-source approach to scanning and
cleaning up these works. Lots of people putting in a little bit of
coordinated effort and releasing the finished product under an open
license so that it cannot be
So?
That statement clearly imlies the Earth's period was shortened aganst some
standard.
If the Earth was the standard, how could it be shortened with respect to
itself?
It can't be. Time standards are atomic now.
-John
===
Calculations indicate that by changing the
Maybe we will end up taking away leap-seconds soon. Just a random
thought given the amount of seismic activity currently going on in the
world.
Steve (Quakecity, New Zealand)
On 15 July 2011 01:40, J. Forster j...@quik.com wrote:
So?
That statement clearly imlies the Earth's period was
In message CALH-g5YuKCDiyGxDf4s-MhHtK=ds7qr8z2st17jrqilwvr0...@mail.gmail.com
, Jim Palfreyman writes:
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
However, atomic time and earth time effectively drift apart, and that is
why periodically we have leap seconds to bring the two closer together
again. So we still need the astronomical measurements.
Think of it as atomic time being the linear reference, and earth time a
course saw tooth, which
On 15 July 2011 02:08, Rob Kimberley r...@timing-consultants.com wrote:
However, atomic time and earth time effectively drift apart, and that is
why periodically we have leap seconds to bring the two closer together
again. So we still need the astronomical measurements.
Think of it as atomic
Sorry, my reply was sent before your comment about speed up. Yes, in theory,
if the earth were to speed up sufficiently we would need to subtract leap
seconds. The old spinning top is unfortunately slowing down (with minor
wobbles and variations such as the recent earthquake in Japan). Minor in
On 7/14/11 6:08 AM, Steve Rooke wrote:
It's a shame these, and other elderly scholarly works, can't just be
released for the greater good, without all this red tape tying them
down. I wonder how much better the world would advance if we could all
go back to the days when we shared knowledge and
At 10:26 PM 7/13/2011, Jim Palfreyman wrote...
But why is it that Caesium Clocks and Hydrogen Masers have an
adjustment
facility?
Cs defines the second, but only at the physically impossible
temperature of absolute zero. Relativistic effects make it so the
second is a different length at
I think you missed my point Jim, sorry if I had not made it clear.
Steve
On 15 July 2011 02:51, Jim Lux jim...@earthlink.net wrote:
On 7/14/11 6:08 AM, Steve Rooke wrote:
It's a shame these, and other elderly scholarly works, can't just be
released for the greater good, without all this red
On 7/14/11 6:40 AM, J. Forster wrote:
So?
That statement clearly imlies the Earth's period was shortened aganst some
standard.
If the Earth was the standard, how could it be shortened with respect to
itself?
It can't be. Time standards are atomic now.
-John
You've raised an interesting
Like this polemic didn't worsen the S/N ratio?
On Wed, Jul 13, 2011 at 10:07 PM, WB6BNQ wb6...@cox.net wrote:
Will,
Did you actually read what I wrote ? I ask because your response, below,
would
suggest a low comprehension rate. I noted a number of your responses fall
into
the same
In message cany2ixooqetude05ikthemp3ghs2sqcgmbpopas+vn4wtw+...@mail.gmail.com
, William H. Fite writes:
Like this polemic didn't worsen the S/N ratio?
If you take a clue from it, it will improve the S/N ratio.
Seeing that you sent a 1-line reply, quoting the entire message,
in a discussion
why reply at all?
From: Poul-Henning Kamp p...@phk.freebsd.dk
To: Discussion of precise time and frequency measurement time-nuts@febo.com
Sent: Thu, July 14, 2011 8:00:43 AM
Subject: Re: [time-nuts] List Noise Level [was...]
In message
This discussion about the Radiation Laboratory series reminded me that in
looking at a book on high vacuum techniques that I purchased in the late
1950's, I was surprised to see it was part of a series on the wartime
development of nuclear energy written at the end of WW-II in a similar
Do you mean Methods of Expermental Physics?
-John
==
This discussion about the Radiation Laboratory series reminded me that in
looking at a book on high vacuum techniques that I purchased in the late
1950's, I was surprised to see it was part of a series on the wartime
So what is the Allan deviation of the earth spinning? :)
___
time-nuts mailing list -- time-nuts@febo.com
To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.
In message 29c8a27967ae5343be5ad7a887c9bd1a188db17...@esi-sbs08.esi.lan, Davi
d VanHorn writes:
So what is the Allan deviation of the earth spinning? :)
I calculated allan/mod-allan on the Bulletin A data some years back,
it's not exactly pretty.
--
Poul-Henning Kamp | UNIX since Zilog
So what is the Allan deviation of the earth spinning? :)
http://www.leapsecond.com/museum/earth/
/tvb
___
time-nuts mailing list -- time-nuts@febo.com
To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the
Anyone got a big file so we can cut those Himalayas down, I'm sure
they are creating a lot of drag :)
Steve
On 15 July 2011 04:01, Tom Van Baak (lab/iPad) t...@leapsecond.com wrote:
So what is the Allan deviation of the earth spinning? :)
http://www.leapsecond.com/museum/earth/
/tvb
tvb...
Bravo!
Tom Holmes, N8ZM
Tipp City, OH
EM79
-Original Message-
From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On
Behalf Of Tom Van Baak (lab/iPad)
Sent: Thursday, July 14, 2011 12:01 PM
To: Discussion of precise time and frequency measurement
Subject:
Hi
If you are running a Cs at high altitude, or worse yet in space -
relativistic effects are pretty significant.
Bob
-Original Message-
From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On
Behalf Of Poul-Henning Kamp
Sent: Thursday, July 14, 2011 10:04 AM
To:
Hi
One would assume that mean sea level / 1 G would be the standard reference
point for the official Cs transition. I've never seen anybody pull out a
gravity meter to set up their Cs though. I suspect that NIST has at least
done the math.
Bob
-Original Message-
From:
In message 90cc90599ce94dc980a448a08c7d2...@vectron.com, Bob Camp writes:
If you are running a Cs at high altitude, or worse yet in space -
relativistic effects are pretty significant.
Absolutely, but you can still pull a new Cs out of the box and it will
run at the same frequency as your old
One would assume that mean sea level / 1 G would be the standard reference
point for the official Cs transition. I've never seen anybody pull out a
gravity meter to set up their Cs though. I suspect that NIST has at least
done the math.
You can do much better than just doing the math.
In
All,
I've been wanting to buy an older pulse generator, but want an accurate
one, and probably one that I can connect to my GPSDO. I would like one
settable to 10 nS, but don't want it variable to there, but switched
between the different pulse rates. I looked at the older HP generators, and
they
In message 201107141334290700.4182d...@smtp.citynet.net, Will Matney writes
:
All,
I've been wanting to buy an older pulse generator, [...]
Look at the HP5359A, it's a slightly special beast, but once you
learn to use it, you get your pulses exactly where you want them.
--
Poul-Henning Kamp
COOL!
From: time-nuts-boun...@febo.com [time-nuts-boun...@febo.com] On Behalf Of Tom
Holmes [thol...@woh.rr.com]
Sent: Thursday, July 14, 2011 10:17 AM
To: 'Discussion of precise time and frequency measurement'
Subject: Re: [time-nuts] Japan Quake May
A Systron-Donner / Datapulse 101 or 101A is an old, but well performing
pulse generator.
Most pulse generators are not particularly precise, but many have an
External Trigger function that can be connected to a precise timing
source.
I'm doing exactly that, using a crystal oscillator at 1 MHz
Hi Will:
The Stanford Research DG535 may be what you're looking for. See:
http://www.prc68.com/I/TandFTE.shtml#DG535
seconds to picoseconds stability, external 10 MHz input.
Have Fun,
Brooke Clarke
http://www.PRC68.com
Will Matney wrote:
All,
I've been wanting to buy an older pulse
FWIW, I used to build and test Systron Donner 101s at their UK subsidiary in
the early 70's. Nice little box!
Rob
-Original Message-
From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On
Behalf Of J. Forster
Sent: 14 July 2011 6:55 PM
To: xfor...@citynet.net; Discussion
On 14/07/11 18:56, Bob Camp wrote:
Hi
One would assume that mean sea level / 1 G would be the standard reference
point for the official Cs transition. I've never seen anybody pull out a
gravity meter to set up their Cs though. I suspect that NIST has at least
done the math.
The gravity may be
On 14/07/11 18:12, Steve Rooke wrote:
Anyone got a big file so we can cut those Himalayas down, I'm sure
they are creating a lot of drag :)
Take your Dremel and a few spare bits and cut it loose. :)
Moving that mass closer into the core would cause some spin-up. Still,
the other effects
On 07/14/11 01:27 PM, Bob Camp wrote:
Hi
I've looked at a random sample of a couple dozen Rb's that are in the 5 to
30 year old range. In about 90% of the cases I'm reasonably certain they
haven't been adjusted since they left the factory. If they still worked,
they all came in at or below +/-
Hi
At least 90% of the units worked fine. Of the other 10% some of the issues
were pretty minor. I only have seen one or two that would not lock.
Bob
-Original Message-
From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On
Behalf Of Dr. David Kirkby
Sent: Thursday,
Hi
Should have added - one of the ones that would not lock was an easy fix
(signal to the connector was the issue).
Bob
-Original Message-
From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On
Behalf Of Dr. David Kirkby
Sent: Thursday, July 14, 2011 4:47 PM
To:
On 15 July 2011 07:38, Magnus Danielson mag...@rubidium.dyndns.org wrote:
On 14/07/11 18:12, Steve Rooke wrote:
Anyone got a big file so we can cut those Himalayas down, I'm sure
they are creating a lot of drag :)
Take your Dremel and a few spare bits and cut it loose. :)
Moving that mass
Unless I'm missing something, it seems to me that this matter has not yet been
discussed among time-nuts:
http://futureofutc.org
From the above website:
A conclusive proposal to fundamentally redefine UTC is scheduled for a vote by
the Radiocommunications Assembly of the ITU-R in January, 2012.
With Bulletin C nr 42, a link to a questionnarie about it is added at
the end (and I think that leap seconds and its convenience or not has
been discussed lots of times in the list :)
From Bulletin C 42:
IMPORTANT: After years of discussions, a proposal to fundamentally redefine
UTC will come
On 7/14/2011 2:02 PM, Steve Rooke wrote:
Well, if everyonel climbed Everest and we all jumped up and down
together, perhaps we could achieve that :)
Cheers, Steve
I can't resist moving this off-topic thread by a giant leap.
I have a 1969 R. Crumb comic book starring Fritz the Cat. In one
Da: jherr...@hvsistemas.es
Data: 15/07/2011 1.06
A: Discussion of precise time and frequency measurementtime-nuts@febo.com
Ogg: Re: [time-nuts] The future of UTC
With Bulletin C nr 42, a link to a questionnarie about it is added at
the end (and I think that leap seconds and its convenience or
Why do you need them to jump at all?
If you got all the Chinese to just stand on a chair, it would increase the
Moment of Inertia of the earth a smitch, and it would slow the rotation
because of the Conservation of Angular Momentum.
-John
===
On 7/14/2011 2:02 PM, Steve Rooke
If they will not observe the leap seconds as the earth times calibration,
it would become unusable in some areas of technology, and or earth time in
itself, or I would think. When the first cesium clock was being built, it
was to be calibrated, I guess one could say, by the astronomical second,
I'm curious in knowing if there are any rules of thumb as to how much better a
reference oscillator needs to be than the device under test when measuring ADEV
?
To provide a bit of context to my question I'm using a HP 5370B to repeatedly
measure the time interval between the 10 Mhz signals
Hi,
I think, the correct definition for a Primary (Time) Standard is not
yet given here, yet.
And I wonder, if there really exists an official definition, in form of
a norm / a standard by BIPM.
There should be one, does anybody know?
I try to give some characteristics which have to be
At 06:51 PM 7/14/2011, iovane\@inwind\.it wrote...
From the above website:
A conclusive proposal to fundamentally redefine UTC is scheduled for a
vote by the Radiocommunications Assembly of the ITU-R in January, 2012.
It's just sheer stupidity. A bunch of people who chose to use the UTC
Mark Spencer wrote:
I'm curious in knowing if there are any rules of thumb as to how much better a
reference oscillator needs to be than the device under test when measuring ADEV
?
To provide a bit of context to my question I'm using a HP 5370B to repeatedly
measure the time interval
Hi
You can be quite sure it's no worse than 2x10^-12. It is pretty common to scale
by square root of two based on a they could be equal assumption.
Bob
On Jul 14, 2011, at 8:32 PM, Mark Spencer mspencer12...@yahoo.ca wrote:
I'm curious in knowing if there are any rules of thumb as to
A scope with one 10Mhz on two Y channels is enough. Say you get 1 cycle
phase displacement every 15 minutes - that's 1E-10. You can get better than
these 10 digits per 15min by counting divisions per minute or so. Not as
nice as a 12 digits/s counter, but way cheaper...
-Original
Some vendors gps receivers cannot handle leapseconds properly, so they may be
pushing to fix the problem this way ;)
Sent From iPhone
On Jul 14, 2011, at 15:51, iovane\@inwind\.it iov...@inwind.it wrote:
Unless I'm missing something, it seems to me that this matter has not yet
been
In message 3209.12.6.201.213.1310686158.squir...@popaccts.quikus.com, J. For
ster writes:
If you got all the Chinese to just stand on a chair, it would increase the
Moment of Inertia of the earth a smitch, and it would slow the rotation
because of the Conservation of Angular Momentum.
1. It's
In message 20110715004035.39b88a0...@locke.alientech.net, Mike S writes:
At 06:51 PM 7/14/2011, iovane\@inwind\.it wrote...
It's just sheer stupidity. A bunch of people who chose to use the UTC
timescale when they should have chosen TAI [...]
Yes, it is just sheer stupidity to postulate random
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