What is Radio Controlled Timekeeping and How Does it Work?

Article By: Logan Hannen

WATCH101 | Dec 27, 2018

What is up, watchfam?! Today, we’re going to take a look at radio controlled timekeeping, how it works, and why it might or might not be useful.

So before we can get into the “how” of radio controlled watches, it’s important to understand the “what.” In short, radio controlled watches, sometimes called atomic timekeeping watches, connect to atomic clocks via radio transmitters and receivers to optimize your watches timekeeping. In plain English, what that means is your watch and the atomic clock talk to each other every night, typically, via radio connection transmitted from a tower to ensure that they’re both on the same page when it comes to exactly what time it is.

Citizen World Chronograph A-T Blue Angels
Source: Citizen

The brand most often associated with this technology nowadays is Citizen, since they have done much to promote the use of the technology in many of their most iconic pieces (see: the Blue Angels World Chronograph above). However, it wasn’t Citizen, or even any Japanese brand that pioneered the technology. No, that honor goes to a little brand from Germany called Junghans…

Junghans Mega 1
Source: 70s Watches

The Junghans Mega 1 is credited as being the first timepiece to incorporate atomic/radio controlled timekeeping. Launched in the 90s, the watch appears on the surface to be no different than your standard LCD screen timepiece, but under the hood it contains a movement designed by Junghans to pick up the atomic timekeeping signal from the tower in Frankfurt, Germany every twenty minutes or so, and is rated at approximately plus or minus one second every million years. No, seriously. (Citizen, for reference, now rates their own tech at accurate to within one second over 20 million years, to give you an idea how far the technology has come). The biggest issue encountered by the Junghans was the fact that it was only programmed to the tower in Frankfurt, meaning outside of Europe, you weren’t going to pick up the signal, and it would default to functioning as a standard LCD watch.

This is, to this day, an issue faced by all radio controlled watches. Since they rely on that signal/connection for their atomic accuracy, any number of factors can get in the way of them actually getting that signal every night. The weather is a big one, since it can interfere with the transmission of signals (anybody with a satellite TV knows exactly what I mean). Equally, sometimes the signal just doesn’t connect, despite being sent out just fine. It’s a major flaw in the technology that, often, just comes down to the distance between you and the towers, and what might be in the way of that.

Atomic Timekeeping Signal Transmission Stations
Source: Unique Watches

In the US, the only tower is located in Fort Collins, Colorado, and while it does claim a radius of coverage enough for the entire continental US, much of Mexico, and plenty of Canada, the signal is strongest in the 1000km immediately surrounding Fort Collins. Outside of that range, it will still work, but its reception will not be as consistent as it would otherwise be. Similar issues can be seen in Europe and parts of Asia, though those area do have multiple towers to counteract this issue some.

Alright geeks, that’s all I’ve got about radio controlled timekeeping. Do you own a radio controlled watch? If so, be sure to share your experiences with it and, as always, keep it classy, watchfam.