Radio waves or radio frequency (RF) is the portion of electromagnetic spectrum with all frequencies between 3 Khz to 300 Ghz. All FM stations transmit information in the form of radio waves.

Some features of radio waves are:

1. Radio waves are transmitted in all direction of free space.
2. Since radio waves are transmitted in all the direction it is also called as omni-directional wave.
3. The operation range of radio wave is 3 Khz to 300 Ghz.
4. The device requires antenna to send and receive radio wave signals.
5. An example of radio wave are FM Radio, televisions, cordless phones.

Radio waves are very useful for multi casting of information. Multi-casting means one sender transmitting signals to multiple receivers. Radio waves can cover larger area and can also easily penetrate thin walls and blockades. On top of all radio waves provides higher transmission rate of signals.