Hi

I agree with their premise that to be useful you need transportable clocks. I’m not quite sure
that something the size (and weight) of a pickup truck is really transportable. Yes one can
move it around (unlike a small mountain)  …. Transporting something like that from here to
Europe and back would make the charges FedEx comes up with on a  40Kg box look
cheap though :)

Bob

Well, I learned a new phrase. I can't wail until the
chronometric-leveling-nuts list gets started!

Tim N3QE

On Thu, Feb 23, 2017 at 3:23 PM, Poul-Henning Kamp phk@phk.freebsd.dk
wrote:

In message 03067739-6291-4E37-831C-875022DBDB5E@n1k.org, Bob Camp writes:

Buy a shipping container with cooling, set the thermostat for
something like +10C, install a ton of good VRLA lead acids, install
suitable telemetry and hand it over the MAERSK, with a manifest
which says "near metacenter, power critical" ?

Wouldn't be that expensive, and you'd know it is pretty close to MSL all along.

--
Poul-Henning Kamp      | UNIX since Zilog Zeus 3.20
phk@FreeBSD.ORG        | TCP/IP since RFC 956
FreeBSD committer      | BSD since 4.3-tahoe
Never attribute to malice what can adequately be explained by incompetence.

On Fri, Feb 24, 2017 at 10:27 AM, Bob Camp kb8tq@n1k.org wrote:

I suspect that it's really only meant to be driven around to labs in
Europe with optical clocks, like LNE-SYRTE and NPL.
I think that you would repack it if you were shipping it overseas.

My one experience of something remotely like this was delivery of our
frequency comb (two full-height 19 inch racks plus the laser on a
large breadboard) from Germany to Australia. It was all working the
same day it was unpacked. But no UHV system of course.

The Chinese one is a bit simpler: it's a single-ion Paul trap, rather
than a lattice clock. Probably less control electronics are needed
too, so maybe it's a bit more mobile.

Cheers
Michael

On Fri, 24 Feb 2017 at 9:00 am, Poul-Henning Kamp phk@phk.freebsd.dk
wrote:

There's a story over at Physics World that compares both systems:

http://physicsworld.com/cws/article/news/2017/feb/20/optical-clocks-hit-the-road

Cheers
Michael

Hi

It’s the things like keeping vacuum systems running that while it’s possible, is not trivial.
I sort of wonder if “transportation” involves one person driving the truck and two people
riding in back as “minders” for all the gear.

This is indeed cool stuff. Their clock is amazing. I’d love to have one. It’s still a massive
piece of gear.

Bob

On 2/23/17 10:49 PM, Poul-Henning Kamp wrote:

It's about $2000 to ship a 20 foot long container (TEU) across the
Pacific from the far east to Los Angeles.  If power is required for the
cooling, it might be more.

I don't think it is transported under power - it is run as a frequency
reference, not a time reference so there's no need to keep it running.
Optical clocks are difficult to keep running continuously, 60% ( best done
so far, if my memory can be trusted) uptime is considered to be very good.
So that means it's not very useful for time comparisons.

Cheers
Michael

On Sat, 25 Feb 2017 at 1:00 am, Bob Camp kb8tq@n1k.org wrote: