Technologies that depends on radio waves:
- AM and FM radio broadcasts
- Cordless phones
- Garage door openers
- Wireless networks
- Television broadcasts
- Cell phones
- GPS receivers
- Ham radios
- Satellite communications
- Police radios
- Wireless clocks
The Simplest Radio:
- Take a fresh 9-volt battery and a coin.
- Find an AM radio and tune it to an area of the dial where you hear static.
- Now hold the battery near the antenna and quickly tap the two terminals of the battery with the coin (so that you connect them together for an instant).
- You will hear a crackle in the radio that is caused by the connection and disconnection of the coin.
A (Slightly) More Elaborate Radio:
Radio Basics: The Parts
- The transmitter
- The receiver
Radio Basics: Real-life Examples
- Modulation: Amplitude Modulation (AM)
- Frequency range: 49 MHz
- Number of frequencies: 1 or 2
- Transmitter power: 0.25 watts
- Modulation: Frequency Modulation (FM)
- Frequency range: 800 MHz
- Number of frequencies: 1,664 (832 per provider, two providers per area)
- Transmitter power: 3 watts