Subcarrier Signals: The Unsung Heroes of the FM Dial

^{How subcarrier radio signals made room for hidden FM stations—and helped ensure that everyone has access to the news}

A version of this post originally appeared on Tedium, a twice-weekly newsletter that hunts for the end of the long tail.

In our modern era, we tend to choose devices with as many functions as possible, and we bristle at the thought of an object with a single use—hence why umbrellas can be so frustrating to carry around. But sometimes, a single use case is exactly the right level of functionality. This is something I’ve been thinking about recently after I got my hands on a fairly large radio that has literally one function: You turn it on and a specific station plays, and there’s no surface-level way to do anything else with it.

This is a weird device—but for its niche, this device, called a subcarrier radio, was perfect. And it was one of many niches that subcarrier radios made possible.

Read more – IEEE Spectrum: