Radio Waves

"Radio waves" transmit music, conversations, pictures and data invisibly through the air, often over millions of miles -- it happens every day in thousands of different ways! Even though radio waves are invisible and completely undetectable to humans, they have totally changed society. Whether we are talking about a cell phone, a baby monitor, a cordless phone or any one of the thousands of other wireless technologies, all of them use radio waves to communicate.
Here are just a few of the everyday technologies that depend on radio waves:

AM and FM radio broadcasts
Cordless phones
Garage door openers
Wireless networks
Radio-controlled toys
Television broadcasts
Cell phones
GPS receivers
Ham radios
Satellite communications
Police radios
Wireless clocks
The list goes on and on... Even things like radar and microwave ovens depend on radio waves. Things like communication and navigation satellites would be impossible without radio waves, as would modern aviation -- an airplane depends on a dozen different radio systems. The current trend toward wireless Internet access uses radio as well, and that means a lot more convenience in the future!
The funny thing is that, at its core, radio is an incredibly simple technology. With just a couple of electronic components that cost few dollors or few hundred rupees, you can build simple radio transmitters and receivers. The story of how something so simple has become a bedrock technology of the modern world is fascinating!

In this article, we will explore the technology of radio so that you can completely understand how invisible radio waves make so many things possible!

Radio Frequencies
A radio wave is an electromagnetic wave propagated by an antenna. Radio waves have different frequencies, and by tuning a radio receiver to a specific frequency you can pick up a specific signal.