Time Dilation tinkering
Hmm, it appears that Symmetricom has an interpretation from IATA which
classifies their rubidium-containing products as non-hazardous.
I went through all of this some time ago because we were shipping
rubidiums about domestically (Australia) and there was no permissible
maximum qty of rubidium allowed on a passenger aircraft. It doesn't
make sense: any event which might have caused exposure of the rubidium
in a clock to water, was likely rather more severe than the effects of
less than 1 gram of rubidium igniting. Hard to argue these things
though.
Cheers
Michael
On Tue, 21 Mar 2017 13:08:56 +0100, you wrote:
On Tue, 21 Mar 2017 13:38:51 +1100
Hugh Blemings hugh@blemings.org wrote:
This got me to wondering if a Rubidium based standard might do the trick
- the Efratom SLCR-101s seem readily available for ~USD$200 mark.
As TvB wrote, a single one will not do the trick. You will need
a stability 1e-14 @1d. IIRC most Rb standards floor out at 1e-12 to 1e-13
somewhere between 1k and 100k seconds. Even the Super-5065 has a floor
of about 3-4e-14 (unless our friends here improved on this already).
There will be a few things that you will need to do, if you want to go
with Rubidiums:
- Stabilize or compensate for environmental effects (temperature, air pressure)
- Build ensembles of Rb clocks.
Hi,
Looking back at an old plot I did of a temperature controlled and air
pressure compensated LPRO against an M12+T, the Hadamard Deviation of
the 1000s averages of the 1PPS measurement was about 5E-14 at 1 day.
A large part of that was likely the GPS, so with a better rubidium
like an FRK-H in a sealed and temperature controlled enclosure you
might be around 1E-14 at 1 day.
The bit that I'm not so sure about is the travelling. A long period of
movement, vibration, magnetic fields, etc. all adding in could
obscure the effects of time dilation.
It might be quite possible, although a nearby mountain and a friend
with a helicopter would make it a lot easier!
Angus.
On 3/21/17 7:12 PM, Chris Albertson wrote:
"flight" there is the word. Why drive up a mountain? Take the clock
with you inside the pressurized cabin of a commercial airliner next time
you are on one of those 10 hour trans=pacific flights. You be taller then
any mountain and it is actually cheaper then a weather balloon.
Can you get a Rb clock past the TSA x-ray machine. Maybe if you ask
first. There must be a way to hand cary specialized equipment.
I hand carry specialized equipment all the time and let it go through
the x-ray. About 1 time out of 10, they'll ask to open it up so they
can swab it for the explosives residue ion mobility machine. Nothing
looks as suspicious as a big block of something with two wires come out
of it (i.e. a 7Amp-hour 12V lead acid battery).
In fact, I did it yesterday with an unlabeled black pelican case holding
a 8x10" PC board with a bunch of cards stacked on it.
While I have my NASA ID and a shipping document describing it, I've
never had to show either. Driver's license, 55 year old guy who looks
like an engineer, and so forth, so maybe I don't look like the notional
threat?
When we hand carry "flight hardware" we do put it in a QA sealed (tape)
antistatic bag, in a QA sealed container, with a special letter that's
been coordinated 24 hours before with TSA. And we don't let it go
through the X-ray (although not for any good reason that I know..).
There's some process you're supposed to follow if they insist on opening
it so you show up at the airport hours ahead of time.
On 3/21/17 10:36 PM, Michael Wouters wrote:
Yes, that's what I was quoted by the Microsemi agent and the price on
Mouser is similar.
The $1568 version was EOL'ed in December 2016; the more expensive unit is
the '2nd generation'.
Ah probably the one that has a good seal and has a rated temperature
wider than 0-35C.
Ive been playing with one for work for the past few weeks and the Nor Easter which blew through NE did not affect short term ADEV with Tau < 1000s and that had a signficant drop in local barometric pressure for several hours
As to long term controlled studies no have not had opportunity to do so yet so that was an off the cuff observation based on the storm and not scientific data.
I'd be interested in any other observations around the same time though if anyone else is running a CSAC in NE
On Mar 21, 2017, at 8:25 PM, Bob Camp kb8tq@n1k.org wrote:
Hi
Ummm … errrr …. it’s a gas cell standard. I’d bet there is a pressure effect.
Bob
On Mar 21, 2017, at 7:01 PM, Scott McGrath scmcgrath@gmail.com wrote:
Noted
However CSAC not subject to barometric effects as Rb units are
Content by Scott
Typos by Siri
On Mar 21, 2017, at 4:18 PM, jimlux jimlux@earthlink.net wrote:
On 3/21/17 12:51 PM, Scott McGrath wrote:
Or perhaps use the Symmetricom CSAC ...
Relatively expensive but might work
The CSAC is 8E-12 AVAR at 1000 seconds, comparable to a Rb.
See also http://tycho.usno.navy.mil/ptti/2011papers/Paper27.pdf
which shows a bit better performance (3E-12 @ 1000s), but the best performance appears to be at 10,000 seconds.
but don't you need better?
Attila wrote> You will need a stability 1e-14 @1d.
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Unhappily, local TSA authorities have--or at least appropriate to
themselves--the prerogative to disregard prior approvals from their
superiors. A former colleague of mine used to hand carry an ultra-high
precision gas dilutor between research sites. She had written approvals
from TSA in DC that included written specifications and interior/exterior
photographs of the electromechanical device. She never had any issues until
one occasion in Wilmington, NC, when a supervisor glanced contemptuously at
her documents and then opened (and irreparably damaged) the measurement
cell to the tune of ~$20K in repairs. A formal complaint to TSA generated a
pro forma letter of apology with a polite refusal to pay the repair cost.
A similar incident occurred some months later in Sacramento. On that
occasion, she literally threw her 60 year old, 97 pound, silver-haired body
across the device, saying that they could arrest her but they would not
destroy another instrument. Airport police were summoned, one of whom had a
lick of sense. He and an indignant TSA 3-striper went off to the phone,
taking her documents, university ID, and passport, the police lieutenant
first telling his officers to prevent the TSA people from touching the
instrument. Half an hour later, they were back, accompanied by a TSA suit
who apologized profusely and personally accompanied her to her gate.
Herman Wouk once described the Navy as a master plan designed by geniuses
for execution by idiots. The TSA seems to have been created in the same
factory.
On Wednesday, March 22, 2017, jimlux jimlux@earthlink.net wrote:
On 3/21/17 7:12 PM, Chris Albertson wrote:
"flight" there is the word. Why drive up a mountain? Take the clock
with you inside the pressurized cabin of a commercial airliner next time
you are on one of those 10 hour trans=pacific flights. You be taller
then
any mountain and it is actually cheaper then a weather balloon.
Can you get a Rb clock past the TSA x-ray machine. Maybe if you ask
first. There must be a way to hand cary specialized equipment.
I hand carry specialized equipment all the time and let it go through the
x-ray. About 1 time out of 10, they'll ask to open it up so they can swab
it for the explosives residue ion mobility machine. Nothing looks as
suspicious as a big block of something with two wires come out of it (i.e.
a 7Amp-hour 12V lead acid battery).
In fact, I did it yesterday with an unlabeled black pelican case holding a
8x10" PC board with a bunch of cards stacked on it.
While I have my NASA ID and a shipping document describing it, I've never
had to show either. Driver's license, 55 year old guy who looks like an
engineer, and so forth, so maybe I don't look like the notional threat?
When we hand carry "flight hardware" we do put it in a QA sealed (tape)
antistatic bag, in a QA sealed container, with a special letter that's been
coordinated 24 hours before with TSA. And we don't let it go through the
X-ray (although not for any good reason that I know..). There's some
process you're supposed to follow if they insist on opening it so you show
up at the airport hours ahead of time.
time-nuts mailing list -- time-nuts@febo.com
To unsubscribe, go to https://www.febo.com/cgi-bin/m
ailman/listinfo/time-nuts
and follow the instructions there.
--
William H Fite, PhD
Independent Consultant
Statistical Analysis & Research Methods
On 3/22/17 12:04 AM, Michael Wouters wrote:
Dear Chris,
I believe IATA prohibits the carriage of any quantity of rubidium on
passenger aircraft.
You have to complete a "Dangerous Goods Declaration" and it then has
to go by cargo aircraft.
I imagine there's a "de minimis" quantity. We didn't declare the cesium
in the CSAC that we hand carried, and I'm pretty sure people have hand
carried SRS Rb sources.
off of the MSDS from Symmetricom/Microsemi
"All Symmetricom’s rubidium product can be shipped both domestically and
internationally as a non-hazardous product. Symmetricom has received
letters of interpretation from both the United States Department of
Transportation (US DOT)Ref. No. 08-0154 and the International Air
Transport Association(IATA) stating that Symmetricom’s rubidium product
are not considered a hazardous Class 4 material in transportation.



On 3/22/17 4:04 AM, Angus wrote:
On Tue, 21 Mar 2017 13:08:56 +0100, you wrote:
On Tue, 21 Mar 2017 13:38:51 +1100
Hugh Blemings hugh@blemings.org wrote:
This got me to wondering if a Rubidium based standard might do the trick
- the Efratom SLCR-101s seem readily available for ~USD$200 mark.
As TvB wrote, a single one will not do the trick. You will need
a stability 1e-14 @1d. IIRC most Rb standards floor out at 1e-12 to 1e-13
somewhere between 1k and 100k seconds. Even the Super-5065 has a floor
of about 3-4e-14 (unless our friends here improved on this already).
There will be a few things that you will need to do, if you want to go
with Rubidiums:
- Stabilize or compensate for environmental effects (temperature, air pressure)
- Build ensembles of Rb clocks.
Hi,
Looking back at an old plot I did of a temperature controlled and air
pressure compensated LPRO against an M12+T, the Hadamard Deviation of
the 1000s averages of the 1PPS measurement was about 5E-14 at 1 day.
A large part of that was likely the GPS, so with a better rubidium
like an FRK-H in a sealed and temperature controlled enclosure you
might be around 1E-14 at 1 day.
The bit that I'm not so sure about is the travelling. A long period of
movement, vibration, magnetic fields, etc. all adding in could
obscure the effects of time dilation.
It might be quite possible, although a nearby mountain and a friend
with a helicopter would make it a lot easier!
No tall mountains in Australia, but...
Pikes Peak in the US is 14114 ft, 4304m and has a road to the top. Of
course the base is at about 5000 ft/1600 m
In EU, there's probably a Seilbahn of some sort pretty high up in the
Alps, although probably not to 4000m.
Aiguille du Midi is 3842m IIRC (cable car base station at about 1000m).
Dave
-----Original Message-----
From: time-nuts [mailto:time-nuts-bounces@febo.com] On Behalf Of jimlux
Sent: 22 March 2017 14:57
To: time-nuts@febo.com
Subject: Re: [time-nuts] Time Dilation tinkering
On 3/22/17 4:04 AM, Angus wrote:
On Tue, 21 Mar 2017 13:08:56 +0100, you wrote:
On Tue, 21 Mar 2017 13:38:51 +1100
Hugh Blemings hugh@blemings.org wrote:
This got me to wondering if a Rubidium based standard might do the
trick
- the Efratom SLCR-101s seem readily available for ~USD$200 mark.
As TvB wrote, a single one will not do the trick. You will need a
stability 1e-14 @1d. IIRC most Rb standards floor out at 1e-12 to
1e-13 somewhere between 1k and 100k seconds. Even the Super-5065 has
a floor of about 3-4e-14 (unless our friends here improved on this already).
There will be a few things that you will need to do, if you want to
go with Rubidiums:
- Stabilize or compensate for environmental effects (temperature,
air pressure) - Build ensembles of Rb clocks.
Hi,
Looking back at an old plot I did of a temperature controlled and air
pressure compensated LPRO against an M12+T, the Hadamard Deviation of
the 1000s averages of the 1PPS measurement was about 5E-14 at 1 day.
A large part of that was likely the GPS, so with a better rubidium
like an FRK-H in a sealed and temperature controlled enclosure you
might be around 1E-14 at 1 day.
The bit that I'm not so sure about is the travelling. A long period of
movement, vibration, magnetic fields, etc. all adding in could
obscure the effects of time dilation.
It might be quite possible, although a nearby mountain and a friend
with a helicopter would make it a lot easier!
No tall mountains in Australia, but...
Pikes Peak in the US is 14114 ft, 4304m and has a road to the top. Of course the base is at about 5000 ft/1600 m
In EU, there's probably a Seilbahn of some sort pretty high up in the Alps, although probably not to 4000m.
time-nuts mailing list -- time-nuts@febo.com
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and follow the instructions there.
On Wed, 22 Mar 2017 07:56:45 -0700
jimlux jimlux@earthlink.net wrote:
In EU, there's probably a Seilbahn of some sort pretty high up in the
Alps, although probably not to 4000m.
But almost: https://en.wikipedia.org/wiki/Klein_Matterhorn
You could start in Sion(500m) or Visp(660m) take the train to Zermatt(1600m)
and from there the cablecar up to Klein Matterhorn(3880m). That would
give a nice 3000m of height difference. From Sion it takes 2.5h to 3h,
from Visp 2h to 2.5h. So you could potentially get up in the morning,
go up, install everything and be back for dinner :-)
If anyone wants to do that, please let me know. :-)
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