[time-nuts] Timing on Ethernet
Dr Bruce Griffiths
bruce.griffiths at xtra.co.nz
Sat Aug 4 21:15:24 EDT 2007
Neville Michie wrote:
> Low frequencies penetrate the ground to some depth.
> However, propagation may vary seasonally as groundwater
> concentrations change.
> cheers, Neville michie
Even without the seasonal variations in propagation, propagation through
the rock etc wont be sufficiently uniform to allow simple calibration
(at the nanosecond level) which rather defeats the purpose of the
system. The equipment required to characterise the propagation delay
variations would itself be suitable for implementing the time
distribution system without the central transmitter.
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