Am 22.03.2017 um 15:56 schrieb jimlux: > On 3/22/17 4:04 AM, Angus wrote: >> On Tue, 21 Mar 2017 13:08:56 +0100, you wrote: >> >>> On Tue, 21 Mar 2017 13:38:51 +1100 >>> Hugh Blemings <h...@blemings.org> wrote: >>> >>>> This got me to wondering if a Rubidium based standard might do the >>>> trick >>>> - the Efratom SLCR-101s seem readily available for ~USD$200 mark. >>> >>> As TvB wrote, a single one will not do the trick. You will need >>> a stability 1e-14 @1d. IIRC most Rb standards floor out at 1e-12 to >>> 1e-13 >>> somewhere between 1k and 100k seconds. Even the Super-5065 has a floor >>> of about 3-4e-14 (unless our friends here improved on this already). >>> >>> There will be a few things that you will need to do, if you want to go >>> with Rubidiums: >>> 1) Stabilize or compensate for environmental effects (temperature, >>> air pressure) >>> 2) Build ensembles of Rb clocks. >>> >> >> Hi, >> >> Looking back at an old plot I did of a temperature controlled and air >> pressure compensated LPRO against an M12+T, the Hadamard Deviation of >> the 1000s averages of the 1PPS measurement was about 5E-14 at 1 day. >> A large part of that was likely the GPS, so with a better rubidium >> like an FRK-H in a sealed and temperature controlled enclosure you >> might be around 1E-14 at 1 day. >> >> The bit that I'm not so sure about is the travelling. A long period of >> movement, vibration, magnetic fields, etc. all adding in could >> obscure the effects of time dilation. >> >> It might be quite possible, although a nearby mountain and a friend >> with a helicopter would make it a lot easier! >> > > No tall mountains in Australia, but... > > Pikes Peak in the US is 14114 ft, 4304m and has a road to the top. Of > course the base is at about 5000 ft/1600 m > > In EU, there's probably a Seilbahn of some sort pretty high up in the > Alps, although probably not to 4000m.
I like the englisch word 'Seilbahn' ;-) Yes, not fully up to 4000 m, but there are in fact quite close to the possibilities I know: 1. Klein Matterhorn, Walliser Alpen, Schweiz Bergstation: 3820 m, 2. Aiguille du Midi, France Télépherique de l’Aiguille du Midi from Chamonix Bergstation: 3777 m Gourmet-Restaurant, 3842 m Enjoy, good luck! Arnold _______________________________________________ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
