[time-nuts] I've designed a GPSDO, but how "good" is it?

Bob Camp kb8tq at n1k.org
Sun Aug 16 20:39:35 EDT 2015


The “wear out” on a Rb is not the same as wear out on a 
Cesium standard. In a Cs, you have a finite number if atoms
loaded in at the factory. When those atoms all travel down the 
tube, it’s dead. In an Rb, the atoms don’t go anywhere. There is
no built in “end of life”. They mostly die from MTBF sorts of things 
due to complexity and high temperatures, There are HP Rb’s 
built many decades ago still running on their original cells.


> On Aug 16, 2015, at 6:10 PM, Attila Kinali <attila at kinali.ch> wrote:
> On Sun, 16 Aug 2015 12:39:19 -0700
> Nick Sayer via time-nuts <time-nuts at febo.com> wrote:
>> I have considered in the past buying a used rubidium standard off eBay,
>> but have hesitated because I don’t know how much life there is left in
>> the tube, and I just have to take it on faith that it’s stable and accurate.
>> I have somewhat more faith in the GPS PPS, but clearly that has limits.
> Don't worry about that.
> The cheap FE-5680 that have been around for a while have a couple of
> years left at least. And even if they go out, you can revive them
> with a hot air gun.
> 			Attila Kinali
> -- 
> I must not become metastable. 
> Metastability is the mind-killer.
> Metastability is the little-death that brings total obliteration.
> I will face my metastability. 
> I will permit it to pass over me and through me. 
> And when it has gone past I will turn the inner eye to see its path. 
> Where the metastability has gone there will be nothing. Only I will remain.
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