A field guide to the radio waves
What is that sound?
The buzzes, warbles, chirps and beeps on your radio all have names. Hear examples, recorded off the air or generated, see what each one looks like, and learn how to tell them apart.
Open the field guide Play Name That Signal
Six sound examples from this guide, three recorded off the air on our own receivers and three made by Cohera, shown side by side like a band display (on the air they sit at different frequencies). Tap a name to learn it, or ▶ to hear it.
This week · Oct 2-6, 2026
Pictures from space, on your radio.
The International Space Station is sending slow-scan TV pictures on 437.550 MHz from Friday to Tuesday. Here's how to receive them.
Coming soon · the Cohera app
Hold up your iPhone. Name the signal.
Cohera is an iPhone app that listens to your radio's speaker and names the signal it hears. When it isn't sure, it says so and shows you what it measured.
Tune in
A sound you're curious about, on your radio, scanner or SDR.
Hold up your iPhone
Near the speaker. No cables and no computer.
Get a name
The signal's name, and its message for modes that can be decoded. Or an honest "not sure", with what it measured.
Cohera doesn't receive radio by itself: it listens to your receiver's sound. No launch date yet.
Famous signals
The sounds people ask about most.
UVB-76, “The Buzzer”
Numbers stations
The Russian Woodpecker
Pictures from spaceGuides