Tom Van Baak wrote: >> I've recently acquired a Rubidium Osc ( Efratom FRS-C 10Mhz) as my >> first venture into this field. It's working as per the spec given >> ,checked against Trimble GPS with 1pps output. >> Can you point me to somewhere where there is a description of the >> physics behind the drift that occurs?Drift is speced as <5x10^-11 per >> month....but why should there be any "drift" at all? >> "Wandering" about nominal I can expect ,but consistent "drift" ? >> Regards >> Peter >> ZL2AYX > > Hi Peter, > > You're off to a good start. With enough days of data > you should be able to measure the drift quite nicely. > > To answer your good question; we all have come to > know that cesium is accurate and rubidium drifts. But > there's much more to the story...
[ Tom's good stuff snipped ] For what it's worth, I have plots with (at the moment) 98 days worth of data showing two HP 5061As and an HP 5065A against GPS (and each other) at http://www.febo.com/time-freq/plots. The drift of the 5065A is hard to discern because what I presume are other environmental effects hide it; in other words, it's pretty darn low. You'll see a whole bunch of files there with hopefully reasonably explanatory names like "cs1-gps-hourly.html" which shows CS1 vs. GPS with hourly averages. The files with "-daily" are 1 day averages, while the ones with "-tail" show the seven most recent days of data with 10 minute averages. Each web page shows the raw phase, the drift-removed phase (using a linear calculation of drift) and ADEV as well as some other statistics. The pages are automagically updated every 15 minutes. I'm hoping to keep the experiment going for a while longer; I'd like to get out to at least 120 days of data. I can make the raw data available if anyone is interested. John _______________________________________________ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts