Hi Well the intent is indeed to set up a number of them, and run clean up OCXO's after them. I'm guessing at least 4 setups and possibly eight or ten.
Bob On Dec 22, 2009, at 11:12 PM, Bruce Griffiths wrote: > Bob > > Some isothermal radiation (thermal) shields between the blanket and the top > of the Rubidium source may also be required. > > Unless you have a hydrogen maser you will need to use 3 rubidium sources each > with its own engine block in order to determine AVAR (using the 3 cornered > hat technique). > FEI claim that their rubidium sources are actually quieter than typical > caesium sources so using a caesium reference isn't as effective for measuring > the short term (< 1day) stability. > > Bruce > > Bob Camp wrote: >> Hi >> >> I agree that if you simply bolt the rubidium to an old engine block and toss >> a blanket over it, you might get some pretty good thermal stability in the >> "hour to couple hours" time period. That's certainly a better approach than >> putting some kind of DC heater (and it's varying magnetic field) near the >> rubidium. >> >> I'm still wondering if they do indeed hit 1x10-13 (as in almost 1x10-14) or >> not. I suspect not. I'm sure that they do indeed get into the 1x10-13's, >> just not sure they get to the bottom of that region. >> >> Bob >> >> >> On Dec 22, 2009, at 8:26 PM, Bruce Griffiths wrote: >> >> >>> Bob Camp wrote: >>> >>>> Hi >>>> >>>> If I randomly pick up a FE 5680A data sheet, I find that it's short term >>>> stability is 1.4/sqrt(Tau) x 10-11. Since I never doubt anything I see on >>>> a data sheet, this immediately tells me I should get 1.4x10-12 at 100 >>>> seconds, and I only have to wait for 10,000 seconds to get to 1.4x10-13. >>>> >>>> Since the temperature performance is at the 1x10-12 / C level, I would >>>> need a room that's stable to *much* better than 0.1 C over a 3 hour period >>>> to get there. I suspect that 0.01C might not be good enough ... >>>> >>>> So here's the question: >>>> >>>> Has anybody run any of the cheap rubidiums (FE or Efratom) in a *very* >>>> stable temperature environment to see how close they get / what the floor >>>> is? I've run through a lot of data on the web, but I haven't really found >>>> what I'm looking for. >>>> >>>> Thanks! >>>> >>>> Bob >>>> >>>> >>>> >>> Figure 7 on the FE5680 page (also on the data sheet) indicates that you may >>> need somewhat less than 3hours to achieve ADEV ~1E-13. >>> 0.01C stability should be adequate.however its not necessary to control the >>> room temperature to this stability if the FE5680 is in an enclosure with a >>> sufficiently high time constant whilst having a sufficiently low thermal >>> resistance so as to avoid overheating the FE5680. >>> >>> Bruce >>> >>> >>> _______________________________________________ >>> time-nuts mailing list -- [email protected] >>> To unsubscribe, go to >>> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >>> and follow the instructions there. >>> >>> >> >> _______________________________________________ >> time-nuts mailing list -- [email protected] >> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >> and follow the instructions there. >> >> > > > > _______________________________________________ > time-nuts mailing list -- [email protected] > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
