How Radio Waves Work

Myles BurkeP11253171TECH 1002

Radio Waves

• Radio waves are found on the ‘electromagnetic spectrum’.

• They have the lowest frequency on this spectrum.• They are used to transmit; TV broadcasts, mobile

phone calls, police radio, AM and FM radio, even radio controlled cars!

• The ‘ionosphere’, which is located between 45 and 250 miles above earth, can reflect radio waves and bounce them across nations. This is how we hear ‘international broadcasting’.

There are 4 types of radio waves

• Long range – Local radio stations• Medium range – Some AM stations e.g. BBC

Radio 5• Very High Frequency – FM stations use this

range such as BBC Radio 2• Ultra High Frequency – This consists of things

such as television transmissions and police radio.

How radios receive and transmit radio waves

• Radio frequencies are picked up by the radio set through the air that the waves travel in.

• Your receiver will receive the available signals whilst you ‘tune’ it and scan through the stations.

• The radio will then interpret the signals and ‘demodulate’ them.

• Finally, your receiver will ‘amplify’ the sounds it receives through either the speakers or headphone socket.

Radio wave usage in other devices

• Early mobile phones use radio waves to transmit information but the waves they use are of a much smaller wave length than waves used by TV and FM radio.

• With older television sets, the large antenna on top of the station would pick up the signal and turn in into visual information on the screen. Most modern TV’s will use a dish that picks up the signals through the sky.

• Radio telescopes use the large wavelengths of light that are emitted by planets and large clouds of gas in space to produce a higher resolution image of objects in space. These special kind of telescopes turn the light produced by stars to create a clear visual image of planets.

• RC Toy Cars use the transmitter (the control in your hand) and the receiver (circuit board and antenna built into the body of the car) to send a radio wave with a frequency of around 27.9MHz that is picked up by the circuit boards in the car. The amount of pressure applied on the trigger of the controller sends an ‘electronic pulse sequence’ to the integrated circuit in the toy car. The electronic pulse sequence is decoded and sent to create the appropriate motor speed to the pressure applied to the trigger. And all this is done in a matter of nano-seconds!

Wireless networks

• The 3 main types of ‘wireless network’ waves are; radio waves, microwaves and infrared.

• Wireless networks include: routers for multiple wireless internet access, remote controls, wireless keyboards, mobile phones and wireless radios

• Wireless communications allow easier access to networks such as the internet and home telephones (where you no longer have to stay by the phone set connected by a wire).

Where different mediums are located on theelectromagnetic spectrum.

References

• http://www.howstuffworks.com/radio.htm• http://www.cites.illinois.edu/101/wireless101.

html• http://www.nrao.edu/index.php/learn/radioas

tronomy/radiotelescope

• http://www.darvill.clara.net/emag/emagradio.htm

• http://www.howstuffworks.com/rc-toy.htm