[time-nuts] Beginner's time reference

John Miles jmiles at pop.net
Fri Dec 11 13:42:11 UTC 2009


> Bill,
> 
> he was planning to spend 100 USD on a used Rubidium, I think a Cs is way 
> over his budget ;-)

Luck has more to do with that than money.  My cheapest cesium standard, at $500, also turned out to be the only one out of three with a healthy tube.  You have to plan on buying a few turkeys.  

If you're shopping for a cesium standard on eBay especially, where the sellers don't tend to know what they're selling or how to test it, it makes sense to bid low and wait until you get lucky.  

> But I agree that a Rubidium has a shorter life span and if you get one 
> for 100 USD on eBay, I would expect it to be "worn out" already.

The LPRO-101 I bought from China recently for ~$100 is in good shape (it's the dotted blue trace in the plot I posted earlier, measured against the aforementioned $500 Cs.)  It locks up quickly, and its lamp voltage is right in the middle of the normal range.  Others have had good results from the same seller, so I think they're actually pretty safe.

-- john, KE5FX




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