> > Date: Thu, 13 Aug 2009 15:34:43 -0700 (PDT) > From: "Rick Karlquist" <[email protected]> > Subject: Re: [time-nuts] OCXO sensitive to gravity > To: "Discussion of precise time and frequency measurement" > <[email protected]> > Message-ID: > <[email protected]> > Content-Type: text/plain;charset=iso-8859-1 > > Tom Duckworth wrote: > > The orientation change is due more to the earth's magnetic flux > effect on > > the oscillator, and less so from gravity. > > > > Tom > > Tom Duckworth > > [email protected] > > Sorry, this is simply incorrect. Magnetic flux from the > earth has no effect on quartz oscillators. There is no > mechanism there. Acceleration definitely affects quartz. > > Magnetic flux could have an effect on atomic standards, > but they normally have magnetic shielding to mitigate > this effect. Orientation (or at least acceleration) > can affect cesium beam standards because the atoms > are flying. Len Cutler put in a fix to mitigate against > this in the 5071A CBT. AFAIK, orientation doesn't affect > Rb standards. >
One of the papers I looked at mentioned that Rb standards are also affected by magnetic fields, but differently. The Rb standard on Huygens apparently had some sort of magnetic compensation circuit in it. Just like for other obsessively good sources, this is at the 1E-13 kind of levels. Googling "Rb Ultra Stable Oscillator magnetic field sensitivity" would probably turn up the paper (since I just glanced at it, saw it wasn't about quartz, and moved on" Cryogenic Sapphire is also affected by magnetic fields. There's just no getting away from an infinite capacity to obsess... _______________________________________________ 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.
