Radio waves and the electromagnetic spectrumWithin the electromagnetic spectrum Radio waves have the lowest Frequency and longestwavelength >1mm and can be far longer than a kilometre 1(St Andrews, n.d).The radio band of the spectrum can be broken down further into the radio spectrum shownbelow. This spectrum is split up to broadcast many devices such as: TV, Wi-Fi as well as thetraditional radio. Figure 1
Advantages of UHF radio frequencyUHF is the useful to use as it is better at penetrating physical barriers such as buildings &mountains than radio frequencies lower down in the radio spectrum.2Because of its higher frequency UHF will cover a lower range but due to its wider frequency rangeit allows more channels to be stacked together. 2The shorter wavelength allows for antennas to be short compared to radio waves lower in theelectromagnetic spectrum. 2‘To increase the limited range of UHF signals the waves can be reflected of charged particles inthe ionosphere than typical line of sight.’ (Wikipedia, 2012)3
Disadvantages of UHFUHF equipment is usually more expensive than other frequency equipment.A decreased line of sight compared with lower frequency radio waves which do not degrade asmuch over long distances. 2UHF frequencies are still prone to atmospheric conditions that effect VHF. Figure2
Radio waves in Wi-fi2 way communication from Wi-fi hub and wireless computer, meaning both devices act astransmitters & receiversOperating frequency of Wi-fi can either be 2.4GHz or 5GHZ within the UHF band (Brain and Wilson, How stuff works)4This is noticeably higher than TV & Radio, the increased frequency is used so more informationcan be carried on the wave.Like many other modern communication applications Wi-fi uses orthogonal frequency-divisionmultiplexing Figure 3
Orthogonal Frequency division multiplexingWhy is it used?In devices that are wireless interference is a common problem, orthogonal frequency divisionmultiplexing reduces this issue by splitting the signal into multiple signals with differentfrequencies. 5 Original signal Transmitting signal Received signal Final signal Figure 4Figure 1 demonstrates orthogonal frequency division multiplexing. The original signal is split intovarious radio signals at different frequencies which are then mixed at the receiver to give a nearperfect signal at the receiver, had the signal not been split interference would have ruined thesignal.
Super high frequency bandThe boundary where radio waves become microwaves and covers a frequency range of 3GHZ- 30GHZ.6Have wavelengths of 10cm to 1cm.7These waves are capable of projecting into space and consequently are used in satellitebroadcasting.Because of their small wavelength they degrade over shorter distances but frequent radio relaystations can solve this problem.SHF are used mainly for point to point communications. Figure 5
Mobile phonesSuper high frequency waves are used in mobile phone technology for a number of reasons.1. The wavelengths of SHF are small allowing mobile antennas to be small and therefore increasing portability.2. Compared to frequencies lower in the radio spectrum they have a much larger bandwidth allowing multiple devices in the super high frequency channel; this allows enough bandwidth for multiple mobile phones across the world.The only drawback is that super high frequency waves degrade over short distances meaning ahigher expense for mobile companies to install signal towers. Figure 6
Additional uses of radio wavesEmergency service radio – for example police radio.Radar and GPS devices – satellite navigation, detecting fish shoals for trawlers or avoidingunderwater obstacles.Medicine - MRI scans & Cancer treatment (removing tumours)8 Figure 7
The future of radio wavesCurrently Nokia is researching possibilities of a phone that could absorb radio wavesto power phone batteries. If this is efficient enough future phones could have an infinite powersupply. 9Though it is not certain some physicists believe twisting radio waves could gives us 100x thebandwidth. Though other physicists oppose this belief there is still much research andexperimenting to be conducted. 10
The importance of radio waves – summary.The uses of radio waves go far beyond traditional radiobroadcasting and are used daily in modern lives. It can be saidthey have increased communication and convenience.It is likely that radio waves will be used in future communicationsalthough we could see the decline in traditional AM/FM radiobroadcasting due to online radio.
Bibliography1) Snow T.P. & Brownsberger K.R. (1997) Universe: Origins and Evolution Ridpath I. (1997) Oxford Dictionary of Astronomyhttp://www.st-andrews.ac.uk/~bds2/ltsn/ljm/JAVA/SPECTRUM/details.html 12/1/20122) Radius gp 300, (n.d ) http://radiusgp300.reviewtrend.com/uhf-versus-vhf-which-two-way-radio-frequency-is-better 12/1/20123) Wikipedia (2012) , http://en.wikipedia.org/wiki/Ultra_high_frequency 17/1/20124) Brain, Marshall, and Tracy V. Wilson. "How WiFi Works" 30 April 2001. HowStuffWorks.com. <http://computer.howstuffworks.com/wireless-network.htm> 18 January 2012.5) Charan Langton. “Orthogonal frequency division multiplexing tutorial” (2004)<complex to real(2004)http://www.complextoreal.com/chapters/ofdm2.pdf> 18/1/20126) No author given “super high frequency” 2004 Argos press http://www.argospress.com/Resources/CommunicationsSystems/suphighfreque.htm 18/1/20127) Tomislav Stimac “Definition of frequency bands (VLF, ELF... etc.)”(n.d) http://www.vlf.it/frequency/bands.html 17/1/20128) William C. Shiel Jr “Magnetic Resonance Imaging (MRI Scan)” Medicine net http://www.medicinenet.com/mri_scan/page2.htm 18/1/20129) David Rotham (2009) “Radio waves: Future way to help keep e-book readers charged up?” Tele read http://www.teleread.com/ebooks/radio-waves-way-to-help- keep-e-book-readers-charged-up/ 19/1/201210) Edwin Cartlidge (2011) “Twisting Radio Waves Could Give Us 100x More Wireless Bandwidth” http://discovermagazine.com/2011/oct/13-twisting-radio-waves-100x- more-wireless-bandwidth 20/1/2012. ImagesTitle page:http://www.robertopiecollection.com/Application/Products/Bush-radios/bush-radios-1GB.asp & http://forums.techarena.in/web-news- trends/995783.htmFigure 1http://news.bbc.co.uk/1/hi/technology/7646348.stmFigure 2http://www.kitguru.net/channel/carl/sony-recall-1-6-million-bravia-tvs-due-to-fire-risk/Figure 3 http://forums.techarena.in/web-news-trends/995783.htmFigure 4 Image created by myself.Figure 5http://www.maplin.co.uk/185cm-satellite-dish-47165Figure 6http://www.gsmarena.com/apple_iphone_3g-pictures-2424.phpFigure 7 http://www.prlog.org/11292973-codaoctopus-colmek-receives-unique-radar-production-contract-from-major-defense-prime.html