Radio waves

The use of radio waves, beyond the use of radio broadcasting!

1. Radio Waves
Matthew Lemay - P11267197
Radio waves, beyond AM radio
broadcasting…

2. •Radio waves work by sending invisible waves, transmitting information such as TV,
internet and music that are picked up receivers and turned into the different types
of media.
•Radios have two parts, the transmitter that takes data (sound) and encodes it into
‘Sine’ waves. The second is the antennas, which are the wires / conductors that
receive electromagnetic waves. The information data is encoded into the pattern
of the wave, like a language that you speak.
• However the antenna will pick up thousands of radio signals at a time, a radio
tuner is necessary to tune in to a particular frequency
•There a number of other technologies that use radio to waves to work, a few
examples being Wireless connections, Television mobile phones and even in
medicine!
•Radio waves can be transmitted over thousands of miles by following the
curvature of the earths surface, skywards or space wave, a very high or ultra high
frequency wave or a microwave.
•The most common radio frequency bands are AM/FM and Television stations.
How they work!

3. How information is transmitted!
•A transmitter or radio transmitter is an electronic device which, with the
aid of an antenna, produces radio waves. The transmitter generates a
radio frequency AC current which is applied to the antenna. When the
antenna is ‘excited’ by the AC current it radiates radio waves.
•Audio Signals are generally transmitted using a cable but a lot of them
require what is called a carrier wave. A carrier wave transmits information
through space as an electromagnetic wave used in radio communication.
A modulator signal from a source is added to the carrier then the
modulated signals are sent along a channel via a cable or radio waves.
•In FM transmission, when the source is transmitted (from a microphone)
the frequency of the sound waves can be added or subtracted in a
proportion from the set FM transmission frequency. The wave amplitude
is determined by the amplitude of the sound waves.
•Am transmission is the opposite, the amplitude of the AM waves is
determined by the frequency of the sound waves and the frequency of
the AM waves is determined by the amplitude of the sound waves.

4. Different types of waves!
•Radio Waves – Visible waves that carry data such as pictures
and sound.
•Microwaves – Microwaves are used to transmit signals for
mobile phone calls. The transmitters and receivers on
buildings communicate with mobile phones that are in range.
•Infrared – These are normally used for military operations,
such as surveillance, tracking and night vision but can be
used in civilian life for things like wireless communication,
remotes and controls and radio forecasting.
•Ultraviolet – Found in sunlight and is also visible and can be
used to change skin colour (also knows as tanning) which
carries health risks such as cancer.
•X-ray – Used for looking at the internal make up of things
such as the human body and bags at the airport.
•Gamma Ray – Gamma rays can be used for sterilising food
and medical items and treatment of certain cancers

5. Aerials!
Aerials pick up (or Radiate) radio waves and convert them into
what you see/hear. There are two common aerials that are
used in modern technology;
The Dipole aerial and the Parabolic dish aerial. The Dipole
aerial consists of two vertical (Or less commonly horizontal)
pieces of metal that conduct the radio waves. Dipole aerials
are used for television signals and high frequency radio
signals.
The Parabolic dish aerial (the big circular dishes, on houses or
space stations). The radio waves are conducted by a small
dipole in the dish and sent through the transmitter. The
radiation patterns used by these aerials makes them very
good for line of sigh communication.

6. Importance of radio waves
Radio waves are extremely important and have
made many, many things possible and without
them we would not be able to of made as much
progress as we have in technology, not just in
our personal lives but professional and even in
wars (UAV’s, Communication, Radar and calling
airstrikes!) Most of us use radio waves every
day, they make communication possible
whether it be a friend in the same road or
someone on the other side of the world!

7. Other technology that uses radio
waves…
•Landline Phones – Phones work by sending signals down a wire, the
microphone changes sound waves into electrical signals and the
speaker changes the signals into waves.
•Mobile Phone – Mobiles use cells. Cells are radio frequency that
are used in the local area, each one has its own frequency and the
cells adjacent to it has different frequencies and they each contain
as base station transmitter or receiver.
•Television – TV signals are transmitted by using a transmitter what
sends the information to a receiving aerial and turner by radio
waves, using ultra high frequency. To receive signal it needs to be
captured by a satellite dish, (A satellite dish is an antenna but its
designed to focus on a specific source) the information is sent to
the dish via satellite dish using radio waves and received by a part
of the dish called the ‘feed horn’.

8. Bibliography
http://www.howstuffworks.com/radio8.htm - How radio works
http://electronics.howstuffworks.com/satellite-tv6.htm - How TV
works
http://electronics.howstuffworks.com/cell-phone-radiation1.htm -
Mobile phones
http://en.wikipedia.org/wiki/Radio_transmitter - Transmitters
http://en.wikipedia.org/wiki/Broadcasting - Broadcasting
http://en.wikipedia.org/wiki/Antenna_(radio) Antenna (Radio)
http://en.wikipedia.org/wiki/Television_antenna - Antenna (TV)
http://en.wikipedia.org/wiki/Radio_waves - Radio waves (Links lead to
how other waves work)
http://uk.answers.yahoo.com/question/index?qid=20061117085931AASFFd8
- (How waves work)