Comment by mikewarot

21 hours ago

I too find myself going down the time-nut rabbit hole. I want a perfect 10 Mhz reference, not necessarily a time of day clock.

I was tempted to go the Atomic Clock route, based on actual cesium oscillators, having found a cheapish ($999) used CSAC on ebay[1]. However, once I started digging into the data sheets[2], I found something unacceptable, Pin 1, labeled "Tune", an analog tuning input.

It was then that I learned that while the Cesium vapor cells were accurate, they aged, and drifted, unlike a properly degaussed and Zeeman harmonic calibrated Cesium Beam atomic clock, which is a primary standard.

Further demotivating was learning they have a 5-10 year service life. That's a lot of money to pay for what's essentially a better OXCO.

I'll stick with GPS disciplined oscillators for now.

[1] https://www.ebay.com/itm/327134074179

[2] https://www.mouser.com/datasheet/2/523/Microsemi_CSAC_Space_...

5 comments

mikewarot

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o_enix_o  20 hours ago

Fascinating, can you share why you need a 10Mhz reference?

  • mikewarot  8 hours ago

    10 MHz is the usual frequency that test equipment uses for external reference. If I could get more than one cheap enough I could do some very interesting home physics experiments.

    For example, does time pass differently inside a can at a million volts potential relative to ground? Both positive and negative rate measurements.

    What about inside a large "A" field at the heart of a large toroid?

    I suppose I could trim them to the same frequency before the experiments, but still $1000 for hone lab experiments is out of my price range.

  • threeio  8 hours ago

    (for me) Sometimes your job might make you run reference time for a large service provider... and then you need multiple reference signals... and then you realize you have spares that are going to be thrown away... and suddenly your home lab becomes way too geeky for you to admit to 99.999999989% of your friends... unless they also are on the same time email list as you ;)