This presentation discusses radio waves and their uses outside of radio broadcasting. It explains that radio waves are part of the electromagnetic spectrum and can range in size from 1 millimeter to 100 kilometers. Radio waves are used for radar, satellite communications, computer networks, television, and mobile phones. Television originally relied on radio wave broadcasting, while mobile phones use radio waves to transmit calls between phones and base stations. Both medical imaging technologies like MRI and cancer radiation therapy make use of radio waves, though their health effects are still debated in the case of mobile phone radiation exposure. The presentation covers these applications and issues regarding radio waves outside of traditional radio broadcasting.
2. Introduction
This presentation will take you through the uses of
AM radio waves outside of radio broadcasting. This
slide show will take you through:
What is a radio wave, and the electromagnetic
spectrum
How these waves are used outside the radio
Some good and bad points about using these
waves.
3. The spectrum
The electromagnetic spectrum is a graph, if you will, of all
the waves known to man. This presentation will be
focusing on the radio waves. Which cover a large part of
the spectrum, the reason for this is radio waves can range
from being 1 millimetre to around 100 kilometres in size
Radio waves can be both man made and natural. Natural
waves are made by astronomical objects and lightening;
hence the reason why when lightening strikes you can
hear interference in your radio.
To the right is an example of astronomical
radio waves.
4. This is Nasas’ version of the Spectrum. So as you can to your left
we have the large ranging radio waves, and to the right we have
our microscopic gamma waves. The pictures underneath the
spectrum are to give a little size reference so as you can see radio
waves can be the size of a football pitch and gamma rays the size
of a nuclei!
Also on this spectrum is visible light for humans, which are found
between infrared and ultra violet rays, so although radio waves
can be the size of a football pitch there is no possible way that
the human eye can see them!
5. How important are these invisible
waves?
As we know AM and FM radio waves are used mainly for
communication, radio to be precise. However they are
also used a lot in things such as:
Radar and other navigation systems (GPS, Satnav etc.)
Satellite communications
Computer networks
TV
Mobile phones
6. TV
When we think of TV we instantly think of broadcast TV, where all of our favourite
shows are played. The importance of radio waves is that broadcast TV was
completely based upon the all ready existence of broadcasting radio systems in
the 1920’s. And it is high powered radio transmitters the broadcast TV signals to
individual TV receivers.
UHF, or ultra high frequency, is the radio frequency that TV uses to transmit;
interestingly enough this is also the same wavelengths that the police and military
use for their radios.
Radio waves are still used for TV broadcasting but it was most notable when TV’s
had antennas on top of them, and when cable companies set a little satellite dish
outside your house.
7. Mobile phones
Mobile phones work because of radio waves; when
someone calls you their voice is transmitted, via radio wave,
to a base station and then is connected to the fixed and
mobile phone network.
These base stations are basically radio antennas, for your
mobile. Each base station can cover a set distance and each
distance is called a cell, so as you move around the country
you are moving cells. This is also the reason why they are
called cell phones.
To the right is an map example of cells
8. Continued………
As we know AM radio waves travel much further
than FM waves and are used for communications,
this is why base stations use AM radio waves, so
they can cover more ground with less base stations.
Also this does mean that (especially in older
phones) the further away you get from a base
station, go into a tunnel or even get stuck in a
lightening storm your phone signal can become
weak, pick up interference or in the case of a tunnel
you can lose signal altogether.
9. Medical uses and dangers
For many years there has been an argument about radio waves used in
mobile phones, there are arguments for and against signs that mobiles can
give off harmful radiation to users. This is because when using your phone
the noise you make is encoded onto a continuous sine wave. It is this wave
and the fact that the electromagnetic radiation given off by mobile phones is
in direct contact with head tissue.
However it’s not all doom and gloom with radio waves as they are used in
medicines for things such as in magnetic resonance imaging (MRI scans)
Also there have been cases of pre-cancerous cells and indeed cancerous cells
being killed via the use of radio waves radiation without side effects or
harming other cells around the cancer. AKA Radiotherapy.
10. Summery
This power point has taken you through:
The basics of what the electromagnetic spectrum is and where AM radio
waves fits in
The importance of these waves
And the uses of these waves outside of radio (including TV, Mobile, dangers
and medicine)
12. The electromagnetic spectrum: radio wave uses, NASA
http://www.darvill.clara.net/emag/emagradio.htm
The electromagnetic spectrum: radio waves, NASA
http://science.hq.nasa.gov/kids/imagers/ems/radio.html
The electromagnetic spectrum, NASA
http://science.hq.nasa.gov/kids/imagers/ems/index.html
Radio waves, Wikipdia http://en.wikipedia.org/wiki/Radio_waves#In_medicine
Television, Wikipedia http://en.wikipedia.org/wiki/Television
Mobile phone base stations – how mobile networks work, Ofcom
http://www.ofcom.org.uk/static/archive/ra/topics/mpsafety/school-
audit/mobilework.htm
Cell phone radiation, How stuff works.com
http://electronics.howstuffworks.com/cell-phone-radiation1.htm
Can radiation treat cancer?, hyscience,
http://www.hyscience.com/archives/2005/05/can_radio_waves.php
Radiation therapy, Wikipedia http://en.wikipedia.org/wiki/Radiation_therapy
