Short Range Radio Device Communications
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Short Range Radio Device Communications Short Range Radio Device CommunicationsIonising radiation and health hazards Ionising radiation and health hazards Radio transmission An electric current in a straight conductor produces a circular magnetic The majority of Irish homes get Internet access via wireless routers.1 fi eld which gets weaker with distance. An alternating current produces Communication between a wireless router and any smart connected Radios and TVs pick up and process radio waves, i.e., electromagnetic an alternating magnetic fi eld. But does this fi eld appear the instant the device is bidirectional. Both devices contain a transmitter and a receiver waves typically ranging in frequency from 30 Hz to 30 GHz. Such current starts or does it take time to travel? and so can ‘talk’ to one another. The communication is complex and the broadcasts require high power transmitters. Most of the RTE radio data rate is very high (e.g. 600 Mbps). Each device can detect errors In the 1850s James Clerk Maxwell began to consider such questions. transmittersWhat operate is atradiation? 200,000 watts (i.e. 200 kW) while the power of Main kinds of ionising λ (m) E (eV) inMain the received sources packets of ofionising data and ‘request’radiation that be sent again. At the some local radio transmitters may be as low as 10 watts. He produced a very comprehensive theory of electromagnetic waves same time the router may be communicating with several other local and calculatedradiation that they should travel at a speed of approximately1 pm 1.24 GeV The pie-chart below shows the average contribution from different sources A candle radiates light and heat in all directions and can devicesof ionising and radiation with remote to the averagecomputers Irish via person. the worldwide makes web. the biggest In Ireland (as in most countries) a person must obtain a licence for radio 300,000,000The diagram metres shows per the second. This led him to propose that light was in Radon illuminate a room. From its source the light appears to travel 10 pm 124 MeV contribution and is the cause of about 250 lung cancer cases each year in ComReg is the statutory body responsible for the regulation transmission. The type of licence depends on the application (mobile wavelength and energy of Wireless routers use 2.4 GHz and 5 GHz bands (2400 MHz & 5000 in straight lines, called rays, and if something blocks the path fact an electromagnetic wave. Ireland. Radon is a radioactive gas that typically seeps into houses from the of the electronic communications sector (telecommunications, phone, amateur radio, air traffi c services etc.). The licence specifi es the electromagnetic waves on a 100 pm 12.4 MeV MHz). As the word ‘band’ implies, each of these is not single frequency a shadow is formed. Light is a form of radiation. scale; photons on ground. It is a product of the radioactive decay of naturally occurring radiocommunications and broadcasting transmission) and maximum power and the frequency ranges or ‘bands’. Maxwell’slogarithmic theory (1867) described the propagation rays Gamma of electromagnetic1 pm 1.24 MeV but a range of frequencies that is divided into several ‘ ’. uranium or thorium. Since 1998, all new buildings in high channelsradon areas must the postal sector. Its remit covers all kinds of transmission wavesthe — next including step up radio have waves.ten times Twenty years later Heinrich Hertz fi rst A dual-band router can use both of these bands. The diagram shows However,When no licence sunlight is isrequired dispersed for bycertain a prism transmissions a spectrum isthat formed we take as Newton more energy and may cause ten 10 pm 124 keV have a radon barrier installed and, in other areas, a standby radon sump networks including: demonstrated the propagation of radio waves. how— a thetype 2.4 of fanGHz that band draws is airdivided from underinto 14 the channels, floor and manyvents it of to which the outside. for grantedfound today. in 1665. For instance, In 1800 Thomas a mobile Young phone showed must that be lightable was to transmitsome kind of times more ionisations. Note that 100 pm 12.4 keV The EPA’s Office of Radiological Protection (ORP) is overlap;Both methods each canband be is used 22 MHzto reduce wide. radon A router entering can the send building. large amounts • Traditional telephone wire wave and he measured the wavelength of light of different colours; they the term ‘gamma ray’ refers to X-rays responsible for ensuring that people and the radio signals as well as receive them. Mobile phones operate in specifi c • Television and radio frequencies range from about 750 nm (red) to about 400 nm (violet). Teselectromagnetic o eectromagnetic radiation coming aves 1 nm 1.24 keV of data very quickly by using several channels at the same time. radio frequency bands and their power is less than 0.4 W. radiation Ionising environment in Ireland are protected from the harmful It is very easy to reduce the radiation dose from radon by reducing the levels of • Radiocommunications including fi xed wireless Also in 1800 Herschel discovered, using a thermometer, that the spectrum A conductorfrom atomic carrying nuclei; a theycurrent are alternating 10 nm 124 eV radon in the home. There is little that we can do to reduce our exposure to other effects of ionising radiation. A smart phone may also have WiFi capability, that is, it uses a specifi ed otherwise identical with high UV • Mobile operators providing voice and data services contained some heat radiation in the dark area beyond the red; we now callone million times per second (i.e. at 100 nm 12.4 eV sources of ionising radiation such as gamma rays, cosmic rays and radiation communicationsthis infra-red protocol radiation and (IR).transmits The following radio signals year (1801) at low Ritter power showed that one megahertzenergy X-rays. or 1 MHz) radiates from the buildings we inhabit, the food we eat and indeed from our own bodies. The ORP• isSatellite a successor services to the Radiological Protection (generally less than 0.1 W). WiFi therefore has a short range ― typically 1 µm 1.24 eV Institute of Ireland which merged with the EPA in 2014. there was some form of radiation beyond the violet end of the spectrum electromagneticThe kinetic energywaves whoseof alpha wave Visible less than which100 metres. could cause chemical change faster than any of the visible colours. lengthparticles is 300 metres.is generally At abetween frequency of 10 µm f (Hz) Measurement of ionising radiation ComReg enables competition in the communications sector It is called ultra-violet radiation (UV). IR 300 MHz5 and the 7 MeV wavelength while that would of beta be just The first thing to decide is what exactly to measure. by facilitating market entry for networks and services and 100 µm 3 THz Source: Wikipedia List of Wlan Channels hat are SRDs 3 metres.particles The generally higher the ranges frequency, from the Theby keyregulating functions access of the to ORP networks are: so as to ensure that 100 keV to 20 MeV. However the 1 mm 300 GHz Option 1: How radioactive is a piece of material; i.e., how many nuclear Today SRDsWhat or ‘short is ionising range (radio) radiation? devices’ are in common use. Below shorter the wavelength. (Their product is consumers, both business and residential, have choice in energy of cosmic rays may be −1 disintegrations occur in it every second. • Educating the public on the risks of ionising are some examples, together with their allocated frequencies: 300,000,000, i.e. the speed of light in m s .) 10 mm 30 GHz Bluetooth is a lower power, bidirectional wireless communication system We now know that visible light, IR and UV form a small part of a much thousands of times greater but Unit: becquerel (Bq); 1 Bq = 1 disintegration per second the radiationservices which they wish to use. In a rapidly evolving wider spectrum of electromagnetic waves. Those with shorter wavelengths is commonly about 300 MeV. 100 mm 3 GHz that also uses the 2400 MHz band but divides it into 79 channels, each of The table shows the part of the Non-ionising radiation This does not indicate how much radiation a person might sector, both in technological and commercial terms, ComReg • wireless local area networks (WLANs) including Wi-Fi Microwaves which is just 1 MHz wide or 40 channels that are 2 MHz wide. Bluetooth • Contributing to Government policy on radiation transmit more energy and often interact with matter as particles called electromagnetic spectrum used by SRDs. 1 m 300 MHz absorb; gamma rays would be much less likely to be absorbed provides the framework for the introduction of new services 5 bands in range: 2.4 − 5.9 GHz divides the data to be transmitted into packets that are sent on different protection matters photons. than alpha or beta particles. such as next generation mobile to support smartphones • Bluetooth devices 2.4 − 2.4835 GHz Non-ionising 10 m 30 MHz channels. The receiving device reassembles the data in the correct order. Option 2: Measure the amount energy absorbed per kilogram due to Electromagnetic radiation whose wavelength is less than about 300 nm Radio The maximum transmission speed is 50 Mbps and the range is typically • andLicensing similar applications. and regulating the possession and use • car isdoor called openers, ionising automatic radiation because gates it can knock electrons off433 some MHz atoms radiation 100 m 3 MHz radiation; this is the ‘absorbed dose’. of ionising radiation in medicine, industry, research How can electromagnetic waves carry about 10 metres.