A short presentation on radio waves, how they are used and what they are used for.

2. What are Radio Waves?
Radio waves are a type of electromagnetic radiation. They can have wavelengths
that are very long compared different types of electromagnetic waves like
infrared or gamma. In fact, they are the longest type of electromagnetic wave and
travel at the speed of light.
Radio waves were discovered over 100 years ago and nowadays they are almost
taken for granted, this is because radio waves do not only provide us with radio
signals/frequencies but they can also carry signals that our televisions and
mobile phones can use.

3. What do Radio Waves do?
Radio waves transmit different sorts of information. This information could be
in the form of music, pictures and/or conversation, this is invisible data and is
contained in a radio wave/s. If radio waves did not exist it would be impossible
to transmit and receive information as easily, if at all.
Radio waves have become increasingly useful with the rise in wireless
technologies. Television and mobile phones are just a couple of things that use
radio waves. Other things that radio waves transmit signals for are: Wireless
networks, GPS receivers, wireless clocks and even small things like garage door
openers.

4. The Basic Radio Wave Structure
Radio waves all have the same basic structure with wavelength and amplitude
being the only things that change if and when a radio wave is modulated in
some way, this could be with sound or other data.
The radio wave diagram below shows an unmodulated radio wave structure. All
unmodulated waves look very much the same.
Amplitude

5. Different Radio Wave Structures
Radio waves can be modulated. There can be amplitude modulation (AM)
waves or frequency modulation (FM) waves.
The radio wave above is an AM radio wave. When sound is added to an AM
radio wave the amplitude (height) of the wave changes giving the wave a more
curved look. However, the wavelength stays the same.
The radio wave above is an FM radio wave. When sound is added to an FM
radio wave the wavelength (space between waves) changes giving the wave a
more varied wave structure, however the amplitude of the wave stays the same.

6. Radio Waves in Television
Radio waves in television are like FM radio waves and not AM radio waves.
Television stations do not switch off overnight, they play constantly giving us
programs to watch throughout both the day and night. This is only possible
because of the way the radio waves that are used in television travel. FM and
TV radio waves travel in the same way – by using transmitters on the surface of
the earth. Using transmitters like these means that, unlike AM radio waves
which bounce off the ionosphere to travel around, there is little or no
interference or distortion to the waves. This gives us a better picture on our
televisions and it also means that our signal stays strong without the signal
needing to be boosted, even through the night.
The diagram below show the line of television and FM radio waves.

7. Radio Waves in Mobile Phones
So many people around the world own a mobile phone. Radio waves are
extremely important in the make-up of a mobile phone, a mobile phone
would not work if radio waves did not exist. When people use their mobile
phones to ring people for a conversation there is a transmitter takes the
sound of your voice and encodes it onto something known as a continuous
sine wave (a sine wave is varied continuously and radiates from the mobile
phone’s antenna throughout space). When the sound has been encoded on
to a sine wave, the transmitter inside the phone then sends the sine wave’s
signal to the antenna, this then sends out the signal. Therefore creating
The ability to have conversations on a mobile phone, without wires or
any other complications.
Mobile phones can lose signal when the radio waves are interrupted,
This is especially noticeable when travelling in a car or on a train when
tunnels distort the signal and conversations can be cut off.

8. References
 Cyber College. Film, Radio and TV [WWW]. Available from:
http://www.cybercollege.com/frtv/frtv017.htm [Accessed 29/01/12]
 Google Images > Blog [WWW]. Available from:
http://blog.sarmento.eng.br/?paged=4 [Accessed 29/01/12]
 How Stuff Works. Cell-Phone Radiation [WWW]. Available from:
http://electronics.howstuffworks.com/cell-phone-radiation1.htm [Accessed 29/01/12]
 How Stuff Works. Radio [WWW]. Available from:
http://www.howstuffworks.com/radio.htm [Accessed 28/01/12]
 The Electromagnetic Spectrum. Radio [WWW]. Available from:
http://science.hq.nasa.gov/kids/imagers/ems/radio.html [Accessed 26/01/12]
 The Electromagnetic Spectrum. Waves [WWW]. Available from:
http://science.hq.nasa.gov/kids/imagers/ems/waves3.html [Accessed 26/01/12]
 Wikipedia. Radio Waves [WWW]. Available from:
http://en.wikipedia.org/wiki/Radio_waves [Accessed 26/01/12]