[time-nuts] GPSDO time constant

John Ackermann N8UR jra at febo.com
Thu Jan 8 13:32:30 EST 2009


I mentioned in another post that I picked up a couple of militarized 
FTS-4100 "fly-away" Cs units.  These have an option installed that adds 
an accelerometer to the OCXO; it's supposed to reduce G sensitivity by 
at least an order of magnitude.

John
----

SAIDJACK at aol.com wrote:
> Hi Magnus,
>  
> all depends - in an aircraft you have 6g+ turn-overs :)
>  
> We make a version of our FireFly-II GPSDO with ultra-low-g sensitivity and  
> ruggedization, that one you can run in a back-pack while doing skating-tricks 
> on  a ramp and you won't see much change in frequency. A bit more pricey on 
> that  OCXO of course.
>  
> Most "standard" oscillators will have about 1-2ppb change after a  turn-over. 
> I have seen some that actually change the Crystal temperature when  turned 
> over, so you can see the initial frequency change due to gravity, then  you see 
> the operating current change, and the frequency slowly drift away as the  
> temperature of the crystal is changed. Bad. Very bad.
>  
> bye,
> Said
>  
>  
> In a message dated 1/8/2009 09:29:41 Pacific Standard Time,  
> brooke at pacific.net writes:
> 
> Magnus  Danielson wrote:
> . . .
>> Most labs would have issues with a 2g  turnover. :)
>>
>> Flipping oscillators that runs is evil and should  be avoided at all
>> times. Should be in the rulebook for  time-nuts.
>>
>> Cheers,
>>  Magnus
> 
> 
> 
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