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 /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 instructions there.
