To add to Bert's note...

Realize that for a GPSDO, (linear frequency) aging-per-day is irreverent, 
almost by definition. What matters is phase noise and short-term stability, 
neither of which you can possibly fix with disciplining against GPS. GPS takes 
care of the rest.

Long-term stability can be critical for non-GPS applications, which is why 
oscillators with daily aging rates in the -11's and -12's are so amazing.

Consider this: if you want to run your bench with a clean 10 MHz source, stable 
to 11 or 12 digits and accurate to 9 digits -- you may be much better off with 
a free-running, stand-alone OCXO with an aging rate down at 1e-11/day than 
using a GPSDO/TCXO. To maintain accuracy of your OCXO just re-tune your OCXO 
*once a year*. Aside from ADEV plots, this is another way to appreciate how 
amazing some OCXO are, any why many of us still troll eBay for high-stability, 
low-noise, low-drift quartz oscillators.

/tvb

----- Original Message ----- 
From: "Bert Kehren via time-nuts" <time-nuts@febo.com>
To: <time-nuts@febo.com>
Sent: Monday, October 20, 2014 4:01 PM
Subject: Re: [time-nuts] LTE-Lite module


Allow me to clarify.
I started out with 7 MV 89 one of it a total loss. The remaining 6 after 3  
month +  burn in show better than 1 E-11 aging per day, 2 closer to 5 E-12. 
 Only two have been tested for ADEV and are close to 1 E-12,  2X not 10  X.
Bert Kehren
 

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