Radio waves are all around us. They're used by cell phones, Wi-Fi routers, TV dishes, and even satellite networks to convey data on thousands of different frequencies. When we unlock a car door with the push of a button or stream music to wireless earbuds, that's radio. It's a simple yet dynamic technology that has been harnessed by creative experimenters for over a century--and now you can join the adventure! Author Fredrik Jansson demystifies the world of radio through a dozen innovative projects, enabling readers to build inexpensive radio circuits such as transmitters and receivers, remote controls, and a working metal detector. Radio concepts are also adapted for the Raspberry Pi Pico, updating classic concepts with contemporary tools for accuracy and power. With more than 150 color images, step-by-step instructions and detailed explanations, and a handy materials list of components and sources, this is the ultimate guide to explore the hidden universe of radio waves!.