[time-nuts] OCXO sensitive to gravity

[Don Latham]

once again, a simple experiment would suffice. Got a refrigerator magnet
handy?
Don

Lux, Jim (337C)
>> -----Original Message-----
>> From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at 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
>> > tomduck at 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...
>
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-- 
Dr. Don Latham AJ7LL
Six Mile Systems LLP
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