[time-nuts] Smart fiber-optic cable ( a reference to Hp's smartclock )

[Magnus Danielson]

On 02/05/2013 12:22 AM, Stanley wrote:
> My thinking is the temperature has the largest effect on change in delay
> of the cable and more data points would better to predict this change.
> The round trip change in delay would collate with a average of the
> temperature along the cable but not necessary as accurate, think cable
> buried at different depths under asphalt and grass. It is just noise if
> we can not correct for it.

If you do a proper two-way time-transfer, you first-degree correct for 
the cable delay. If you do it at sufficiently high rate, you track the 
temperature shifts without much residue leaking out. It is scaringly 
unfancy stuff you need to do. It's just care to details.

Even doing time-transfer over a fibre-pair works relatively well.

What distances do you need? What precision do you need? Would 
calibration be possible?

Cheers,
Magnus