[time-nuts] 10811 crystal orientation

Bob Camp lists at cq.nu
Fri Jul 10 22:04:49 UTC 2009


On Jul 9, 2009, at 11:55 AM, Magnus Danielson wrote:

> Richard (Rick) Karlquist wrote:
>> Bob Camp wrote:
>>> Hi
>>>
>>> I think that if you dig into it, you will find that there is a  
>>> polarized light process to orient the blank before the base plate  
>>> is applied.
>>>
>>> Unfortunately for the discussion at hand, the direction of maximum  
>>> G sensitivity is still random relative to the mount.
>>>
>>> Bob
>>> KB8TQ
>> To clarify:  the crystal PACKAGE (base plate) is randomly oriented  
>> in the 10811 casting.  Therefore, it doesn't matter if the blank is  
>> positioned in some definite orientation with respect to the base  
>> plate.
>
> Around the blanks rotational axis I assume. That should stay the  
> same, right? It's just one rotational freedom and not three that is  
> there.
>
> Cheers,
> Magnus
>

Hi

Yes, the blank is round and you need to figure out which way to rotate  
it within the crystal holder. The idea is to minimize mount stress.  
It's done on both double rotated crystals and on AT's.

Since in-plane mount stress is not the "whole story" in terms of G  
sensitivity,  you still get a random orientation (within the plane)  
for the G sensitivity vector.

Bob
KB8TQ



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