Some caution is in order as some ferrites used in RF transformer coils may be permanently altered by application of a strong magnetic filed. Testing at lower fields first would be safer. Setupo a pair of Helmholtz coils and excite them with low frequency AC and look for associated sidebands in the oscillator output. NB a spectrum analyser is unlikely to be sensitive enough for this.
Bruce Don Latham wrote: > once again, a simple experiment would suffice. Got a refrigerator magnet > handy? > Don > > Lux, Jim (337C) > >>> -----Original Message----- >>> From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On >>> Behalf Of Rick Karlquist >>> Sent: Thursday, August 13, 2009 3:35 PM >>> To: Discussion of precise time and frequency measurement >>> Subject: Re: [time-nuts] OCXO sensitive to gravity >>> >>> 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 >>>> tomd...@comcast.net >>>> >>> 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. >>> >>> >>> >> Hmm. We're investigating just this at work, in connection with things >> destined to orbit Jupiter, where we expect to see a periodically varying >> flux as the spacecraft spins. The quartz is insensitive, but the mounting >> isn't necessarily insensitive to magnetic fields, especially if any >> magnetic materials (i.e. Kovar seems to be of interest) are used. >> >> If you have any circuits sensitive to DC offsets, then a varying magnetic >> field can cause problems (e.g. the VCO input in a PLL). >> >> I suppose it depends on "how good" the oscillator is expected to be... >> >> _______________________________________________ >> 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. >> >> > > > _______________________________________________ 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.
