By Nathaniel Padbury

P11257338

The uses of AM waves outside radio broadcasting

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.

Introduction

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.

The spectrum

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!

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

How important are these invisible waves?

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.

TV

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

Mobile phones

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.

Continued………

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.

Medical uses and dangers

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)

Summery

Thank you very much for listening,

any questions?

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