A recent discussion of clock/calendar chips on one of the local email lists coincided with me reminding myself that I own a very decent clock with respect to drift.
I’m taking my amateur radio station apart (hadn’t turned the radio on in two years despite the sunspots peaking again: a very clear indication of my remaining interest in this hobby). I just moved the station clock indoors. It had been in an unheated room and I’m sure the time hasn’t been set in at least three years. The temperature went up and down constantly out there, to the upper 30s in the winter and upper 80s in the summer (the volume of air in the surrounding barn levels things out). Anyway, I just set the clock to EST and had to fix the minutes: off by two. So figure it was off by 179 seconds after 36 months. That’s 2ppm, what would be considered extremely good in a clock calendar chip such as the DS3231. All kidding aside, Radio Shack makes some decent stuff!