[time-nuts] OCXO sensitive to gravity

Don Latham djl at montana.com
Sat Aug 15 22:05:35 UTC 2009


We used an Rb magnetometer to measure total charge change due to lightning
in 1964 or thereabout-
Don Latham

Tom Van Baak
> Although we time-nuts prize quartz oscillators that are highly-stable
> and well-insulated from environmental effects there is an entire
> industry doing the exact opposite -- using quartz as a sensor.
>
> Some of the best thermometers are based on quartz oscillators
> (hp 2804A) cut to maximize, rather than minimize, their tempco.
>
> And billions of accelerometers (from air bag sensors to Wii game
> controllers to the iPod touch and iPhone) have been produced in
> the past decade. Google words like MEMS Quartz Accelerometer.
> Also for Quartz Rate Sensor QRS.
>
> I've seen quartz resonators used to measure to impurities in the
> making of semiconductor wafers -- they measure the change in
> frequency of an exposed quartz resonator as atoms fall on the
> exposed crystal and change its frequency. Note that a 1 mm
> quartz crystal is only about a million molecules thick. So adding
> a layer of only 1 atom will change the frequency in the ppm range.
> We can measure a thousand or million times better than that.
>
> As you feel your heart beat, google for Quartz Pressure Sensor
>
> Quartz is really quite amazing. It's almost a shame to shield it
> from everything so all they have left to do is try to measure time!
>
> One other note: rubidium vapor frequency standards are much
> more sensitive to magnetic fields than cesium beam standards.
> I've heard that military sub-hunting sea planes use deliberately
> un-shielded rubidium clocks to detect hidden submarines. Google
> for words like Rubidium Magnetometer ASW P-3 Zeeman
>
> As always, one man's error is another man's signal...
>
> /tvb
> http://www.LeapSecond.com
>
>
>
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-- 
Dr. Don Latham AJ7LL
Six Mile Systems LLP
17850 Six Mile Road
POB 134
Huson, MT, 59846
VOX 406-626-4304
www.lightningforensics.com
www.sixmilesystems.com




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