How to Explore the Radio Spectrum, and What you can Find

Flying around you at this very moment are thousands of man-made radio signals. With a $20 USB dongle, you can visualize and decode a large number of them.

I’m sure you’re aware of humanity’s reliance on radio waves for practically every communications task. After all, how could it get much better? In a tiny fraction of a second, you can send millions of bits of information to another point thousands of feet away, all with very little power.

We also use radio waves for much more than cell-phones and walkie talkies. We use radio to communicate with our deep space probes (although this takes a while), pinpoint our exact locations on the surface of the Earth, and even cook our food.

Despite the utility of lower-frequency electromagnetic waves to modern society, humanity’s primordial ancestors never evolved the ability to sense and interact with radio-frequency (RF) electromagnetic radiation. Our sight remains limited to electromagnetic waves in the range of visible light. Some animals can sense lower-frequency infrared radiation, but this is still many orders of magnitude higher in frequency than radio waves.

Given how useful radio waves are, we have created many devices to detect and measure them. One such class of device, called software-defined radios (or SDRs), can be…