[time-nuts] Non electrical time-nuttery

Bob Camp lists at cq.nu
Sun Jan 10 02:13:13 UTC 2010


Hi

It's probably independent of the light as long as you have a linear spring. My concern is that you likely do not have a completely linear spring.

Since by definition you can't use an electric light, some kind of gas light would be an option. I suspect that if you regulate pressure you could keep the light pretty constant.  Dry gas for both the fuel and oxidizer would take out the humidity issue. 

Bob


On Jan 9, 2010, at 8:39 PM, J. Forster wrote:

> No, I don't think so.
> 
> The period of a pendulum is independent of the amplitude of the swing to
> first order, at least. I think the same applies to a torsional pendulum.
> Maybe moreso if the fiber is a linear torsional spring.
> 
> -John
> 
> =================
> 
>> Hi
>> 
>> All you would still need is a way to regulate the light intensity.
>> 
>> Bob
>> 
>> 
>> On Jan 9, 2010, at 7:58 PM, J. Forster wrote:
>> 
>>> Consider this:
>>> 
>>> A torsion pendulum with blackened vanes on the perimeter suspended from
>>> a
>>> fiber. Part way up the fiber is an optical shutter and a small fixed
>>> magnet so the shutter is stable in two positions with some hysteresis.
>>> One
>>> position lets light fall on the vanes, one does not.
>>> 
>>> This would make an optically pumped pendulum w/ no electronics.
>>> 
>>> -John
>>> 
>>> ==============
>>> 
>>> 
>>> 
>>> 
>>>> Hi
>>>> 
>>>> If you abandoned the non-elecronic side of the requirement, you could
>>>> hit
>>>> it with a pulsed LED and probably get phase data off of a couple of
>>>> photo
>>>> detectors.
>>>> 
>>>> Crazy stuff ...
>>>> 
>>>> Bob
>>>> 
>>>> 
>>>> On Jan 9, 2010, at 6:21 PM, J. Forster wrote:
>>>> 
>>>>> Maybe you could "pump" the pendulum optically, using a beam of light,
>>>>> like
>>>>> those glass bulb "radiometers" they sell that spin on a sunny window
>>>>> ledge.
>>>>> 
>>>>> -John
>>>>> 
>>>>> =============
>>>>> 
>>>>> 
>>>>> 
>>>>>> Like a magnetically coupled escapement
>>>>>> Sent via BlackBerry by AT&T
>>>>>> 
>>>>>> -----Original Message-----
>>>>>> From: Bob Camp <lists at cq.nu>
>>>>>> Date: Sat, 9 Jan 2010 12:36:11
>>>>>> To: Discussion of precise time and frequency
>>>>>> measurement<time-nuts at febo.com>
>>>>>> Subject: Re: [time-nuts] Non electrical time-nuttery
>>>>>> 
>>>>>> Hi
>>>>>> 
>>>>>> How about a rotary pendulum on a quartz fiber spring with some kind
>>>>>> of
>>>>>> trick magnets to drive it  / read it out? Put the pendulum and spring
>>>>>> inside an evacuated glass envelope to get around the vacuum pump
>>>>>> issue.
>>>>>> The enclosure could be pretty small.
>>>>>> 
>>>>>> Drive the magnets with a second external clock, and feedback
>>>>>> compensate
>>>>>> it. Let the external clock do all the readout via a very normal gear
>>>>>> and
>>>>>> pointers system. The trick would be getting the feedback loop to work
>>>>>> purely mechanically with enough gain to "unload" the master pendulum.
>>>>>> 
>>>>>> Bob
>>>>>> 
>>>>>> 
>>>>>> On Jan 9, 2010, at 2:07 PM, Lux, Jim (337C) wrote:
>>>>>> 
>>>>>>> OK.. So we're moving back in electrical technology....
>>>>>>> But what about mechanical?  Could modern technology get a
>>>>>>> substantial
>>>>>>> (>order of magnitude) improvement over 19th century chronometers
>>>>>>> (either
>>>>>>> pendulum or balance wheel or whatever).  I know there's some really
>>>>>>> good
>>>>>>> quartz fiber torsional spring schemes, but I think they still need
>>>>>>> electrical means to keep them moving and to read it out.
>>>>>>> 
>>>>>>> So how good can one do with a mechanical, hydraulic, (or chemical, I
>>>>>>> suppose) system?  Let's assume it has to have a "direct" readout
>>>>>>> that
>>>>>>> is
>>>>>>> human readable by a causal bystander.  (this starts to sound like
>>>>>>> the
>>>>>>> 10,000 year clock or whatever it is..)
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>>>>>> 
>>>>>> 
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>>>>> 
>>>>> 
>>>>> 
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> 
> 
> 
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