[time-nuts] Improving the stability of crystal oscillators

John Miles jmiles at pop.net
Sun Oct 14 17:15:10 EDT 2007

> The required depth depends on the soil diffusivity and the temperature
> stability required.
> It is instructive to install thermometers at depth intervals of a foot
> or so and record the temperature fluctuations experienced by each
> thermometer.
> This was first done around 1860 by Forbes.
> I repeated the experiment in 1966.

There was an interesting bit in the last Agilent Measurement Journal about a
product that uses an ordinary communications-grade fiber as a thermometer.

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