[time-nuts] Time Dilation tinkering

Tom Van Baak tvb at LeapSecond.com
Tue Mar 21 19:02:27 EDT 2017

Scott McGrath wrote:
> Or perhaps use the Symmetricom CSAC ...

Chris Albertson wrote:
> Get a weather balloon.  Or there might already be an amateur group that
> launches these.  Balloons can go much higher than your local mountains.

You'll both be interested to hear that CSAC+balloon was proposed for the "Genius by Stephen Hawking" TV program and, yes, we were in touch with amateur high altitude balloon groups. The producer rightly thought that a small atomic clock going up in a helium balloon would make dramatic video for a time dilation demonstration. Symmetricom / Microsemi donated a SA.* series clock to the effort.

I got involved on the science and engineering side of the equation. Spent a month trying to make it work and in the end the balloon idea was dropped. Just too hard, and too uncertain, and would require many more months of R&D, and finger crossing. So that's why, instead, I drove six calibrated 5071A down to Tucson for a conventional mountain-valley time dilation experiment -- which I knew from prior experience would work, especially with 3x redundancy. http://leapsecond.com/great2016a/

Note that miniature Rb and Cs clocks (such as those sold by Microsemi) are very small, ultra light, and amazingly low power -- but their long-term stability (including environmental effects) is a hundred or even a thousand times worse than a 5071A/001. This is not to say CSAC are poor clocks. In fact they have a superb mass/power/size to adev ratio, and thus there are many unique applications for them. But they are not designed to be laboratory-quality frequency standards


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