
xii Make: Radio
THE MYSTERY AND MAGIC OF RADIO
Radio waves are all around us, transmitting a fantastic variety of data
on thousands of different frequencies. Whenever a piece of electronic
equipment communicates via electromagnetic radiation, it is a form of radio:
• Your cell phone emits a radio signal when you speak into it.
• Emergency responders exchange radio messages via walkie-talkies.
• An Ethernet router that uses Wi-Fi to connect with your computer is a
form of radio.
• Bluetooth is a radio link between devices such as a phone and wireless
headphones.
• If you have a little plastic box in your car that opens your garage door when
you ...