[time-nuts] Quartz oscillator slow drift/aging

[Majdi S. Abbas]

On Mon, Dec 02, 2019 at 12:30:44PM -0700, AC0XU (Jim) wrote:
> I have a FPS 1150A quartz oscillator with the 1 PPS disciplining 
> option. With the frequency control set to "manual" I can use the digital 
> thumbwheel control to set 10 MHz correctly. However, for two weeks there 
> has been a steady drift upwards of about 2E-10 per day. I have not seen 
> this behavior in other similar oscillators - the magnitude of the drift 
> seems greater than expected. Any ideas what could be happening?  I have no
> idea how long the unit was unpowered before I got it - it needed repairs - 
> it may have been years. Is this normal? Should I  expect the drift to 
> decrease over time? Etc?

	Crystal oscillators will retrace their old aging curve pretty
quickly when switched back on.  Run it for a few more weeks and then
evaluate it.

	4-6 weeks is a typical figure.

	--msa