[time-nuts] Time Dilation tinkering
EWKehren at aol.com
EWKehren at aol.com
Fri Mar 24 09:35:32 EDT 2017
Around 2000 when Offshore Navigation went Bell up because of GPS, I
purchased more than 50 Cesium Standards most HP 5061A but also some FTS units.
Most HP units went in a crate to Germany, kept a few, but kept all FTS units.
I did take one FTS on the plane from Miami to Frankfurt operating,
fascinated by what HP had done. This was before my time nuts days and had no way
to measure any thing, but it fit nicely in a carry on with wheels about 50
lb, 20 lb 12V 18 A batteries, 20 lb FTS 5000. No problem at security, while
waiting for boarding had it plugged in the Admirals Club and on arrival
plugged it in to the 12 V of the rental car.
Having a life long Platinum 5 Million Mile card and First Class may have
helped. Having twice in the last 30 years moved my lab to and from Germany
I have carried some pretty heavy and large equipment on board with no
problem ever.I still have the Samsonite suit cases that fit 19 inch instruments.
Bert Kehren
In a message dated 3/23/2017 12:00:34 P.M. Eastern Daylight Time,
eb4apl at gmail.com writes:
Not mentioning that the clock traveled in a passenger seat (even with
the seat belt fastened). The vision of a big box with cables and a good
sized clock ticking (it was a Patek Philippe movement in early HP
Cesiums) frightened some passengers and the person accompanying the
clock had to give a lot of explanations. The use of the word "atomic"
worsened things somewhat.
(Memories from Apollo flights good times)
Regards,
Ignacio, EB4APL
El 23/03/2017 a las 12:33, Bob Camp escribió:
> Hi
>
> Back before GPS and similar systems, hauling Cs standards on commercial
aircraft was
> a bit more common than it is today. One of the critical tricks of the
trade was knowing where
> each power outlet was on a specific plane and how close it was to this
or that seat. The next
> trick was knowing how to talk the crew into letting you plug the gizmo
in the seat next to yours
> into that outlet. Sometimes the magic worked and other times you had to
depend on your
> battery pack. Needless to say, getting through the over ocean travel
process with a dead
> standard was not good news.
>
> Bob
>
>> On Mar 22, 2017, at 10:59 PM, Bob Bownes <bownes at gmail.com> wrote:
>>
>> It's not getting one past the airport authorities that's the issue.
It's getting one that's powered up past them. ;)
>>
>> Written from about 10,000'. :)
>>
>>> On Mar 22, 2017, at 20:15, Tom Van Baak <tvb at LeapSecond.com> wrote:
>>>
>>> Chris Albertson wrote:
>>>> Why drive up a mountain?
>>> "Because it's there" ;-) And because there's a paved road, and it's
free, and there's a place to stay overnight, and the mountain doesn't move.
Plus a car makes a good portable time lab; you can share the experience
with family or students or visiting time nuts; and a number of technical
reasons.
>>>
>>> But most importantly: you can remain at altitude as long as you want
-- in order to accumulate just enough nanoseconds of time dilation to meet
your experiment's S/N goal -- without running into (or much worse, going
beyond) the flicker floor of your clocks.
>>>
>>> There are several different ways to measure time dilation with atomic
clocks. Some notes here:
>>> http://leapsecond.com/pages/atomic-tom/
>>>
>>>
>>>> Take the clock with you inside the pressurized cabin of a commercial
airliner
>>> Yes, and this has been done many times. The first (1971) and most
famous of all traveling clock relativity experiments is:
>>> https://en.wikipedia.org/wiki/Hafele%E2%80%93Keating_experiment
>>>
>>> For vintage hp flying clock articles see:
>>> https://www.febo.com/pipermail/time-nuts/2013-January/073743.html
>>>
>>> Two modern examples are described here:
>>>
>>> "Time flies"
>>> http://www.npl.co.uk/news/time-flies
>>>
>>> "Demonstrating Relativity by Flying Atomic Clocks"
>>> http://www.npl.co.uk/upload/pdf/metromnia_issue18.pdf
>>>
>>> /tvb
>>>
>>> ----- Original Message -----
>>> From: Chris Albertson
>>> To: Tom Van Baak ; Discussion of precise time and frequency measurement
>>> Sent: Tuesday, March 21, 2017 7:12 PM
>>> Subject: Re: [time-nuts] Time Dilation tinkering
>>>
>>> "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.
>>>
>>> On Tue, Mar 21, 2017 at 7:03 PM, Tom Van Baak <tvb at leapsecond.com>
wrote:
>>>
>>> But attached is one of the first plots where I put a SA.32m in a
home-brew vacuum chamber and pulled down to a few inches of Hg for a few hours
to simulate the low pressure of a flight up to 50 or 90,000 ft. For a high
altitude relativity experiment -- where you'd like your clock to remain
stable to parts in e-13 and not accumulate too many stray ns -- it's not a good
sign when your clock changes by 2e-11 (that's more than 1 ns per minute)
just because of ambient pressure changes.
>>>
>>>
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