[wkat4242]

Actually that F91W does not keep very good time.

There pretty excellent if you keep them on a shelf bit if you run around outside in the hot and cold (you know, like people use a watch) they'll deviate quickly. Because they don't have a temperature controlled (or even compensated) oscillator. A real TXCO (basically putting the crystal inside a temp calibrated oven) is not feasible on a watch battery but compensation sure would be.

[ben_w]

I picked it not because it's good, but to illustrate the cheapest digital is still better than any analog mechanism that money can buy.

[wkat4242]

Ah ok,I didn't realize analog watches were that bad.

[minetest2048]

> A real TXCO (basically putting the crystal inside a temp calibrated oven) is not feasible on a watch battery but compensation sure would be.

Nitpick: You're thinking about OCXO for crystals inside an oven, TCXOs are temperature compensated crystal oscillators