[tverbeure]

This year, I bought an HP 5334A universal counter for $60 at the flea market. A week later, I bought an HP 5384A frequency counter through Craigslist from a local in Los Altos.

When I told him about the 5334A purchase, he replied “Oh yeah, I was the project lead for that one.”

You can see the loot here: https://tomverbeure.github.io/2023/06/16/Frequency-Counting-.... I bought another HP counter today in Monterey… It’s like bicycles: the perfect amount to own is +1.

[mikewarot]

I have a friend whose bucket list included owning an Atomic Clock. We ended up repairing several HP 5061Bs along the way. We did the X/Y axis oscilloscope comparison of two clocks, it was a diagonal line when we went to lunch, and the same diagonal line when we got back... amazing stuff.

I think that makes me a qualified Quantum Mechanic. ;-)

[tverbeure]

Do my Rubidium references (yes, plural) count? They're not quite as stable as a Cesium-based 5061, but I believe they use the same principle so they’re technically also atomic clocks.

[mikewarot]

Yes they count, but they use a completely different principle of operation.

The Cesium beam clock actually has a stream of atoms flowing through it, which is finite, leading to tube lifetimes of a decade or less.

The rubidium clock has a number of cells of rubidium gas, one of which is a light source, the other of which gets hit with RF, and if the frequency is just right, it absorbes about 1% of the light before it hits the detector.

A much smaller physics package, to be sure. They do drift, though, a tiny bit.