[time-nuts] Reeeely long term HP 5065A drift rate (13 year!)

Tom Van Baak tvb at LeapSecond.com
Tue Jun 30 07:58:33 UTC 2015

> Did you take into account difference in height (if it was significantly different)?

Hi Jim,

Two things about altitude and clocks. First, the unit was calibrated by Corby 13 years ago and again now. Presumably same house; same altitude. So there is no net before-vs-after height difference to cause some kind of relativistic effect.

And second, even if you took the gravitational effect on atomic clock frequency into consideration, it's still only about 1e-16/m or 1e-13/km. So if you lived in Boulder, CO (~ 5400 feet) the effect is just 1.8e-13. His measurement of ~2e-11 is still a hundred times greater than a relativistic effect. And of course, as soon as you ship the clock back to Corby near sea level, it goes back to its normal rate. So it doesn't matter if the 5065A lived 13 years at sea level or on a mountain or in a deep well or was installed in the space station. The key is that it was recently recalibrated at the same location it was originally calibrated. Make sense?


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