--- Ulrich Bangert <[EMAIL PROTECTED]> wrote:
> John, > > > offset that changed annually. IIRC, it was > typically something like > > 300x10e-10. > > Agreed! And that is what the manual says its good > for! > > However, the question remains why different physics > packages need > DIFFERENT thumbwheel settings in order to achieve > the SAME time scale. > > 73 de Ulrich, DF6JB > I've read the answer last week on the forum... (sorry i don't remember who gave the answer...) It's simple: The technology used on cesiums CAN NOT be applioed on Rubidiums. With Cesium, high end techniologies like fountains or beans can be used, and if i understand well, with these technologies, PURE CESIUM is used, so there is NOTHING that can affect or "pull" the resonance of cesium from it's natural resonance. (9 192 631 770 Hz). With rubidium, buffer gases must be used, and these gasses "pull away" the resonance away from Rubidium's natural resonance. And that is the source of all our problems with rubidium: Buffer gas/rubidium evaporation/absorption will affect the frequency "pulling", thus the drift in Rubidiums. This also explins why two rubidiums clocks wiill have different settings (Rb/buffer mixture tolerances). With Cesium, no pulling, with rubidium, some pulling. That's why Rubidiums aren't primary standards. If we could build a Rb (or ANY OTHER element) atomic clock with the same technology that we use with Cs (total element purity), there wouldn't be any pulling over time and Rb's would be considered primary standards. Hope this explanation will help! 73 de Normand Martel VE2UM ____________________________________________________________________________________ Sponsored Link $200,000 mortgage for $660/mo - 30/15 yr fixed, reduce debt, home equity - Click now for info http://yahoo.ratemarketplace.com _______________________________________________ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
