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Research
This is basic information on radio waves and other similar topics to help understand more about our project.
Contents
Radio Waves
What is a Radio wave? A radio wave is the lowest frequency of electromagnetic radiation. The electromagnetic spectrum, in order of increasing frequency, starts with radio waves, then microwaves, infrared radiation, visible light, ultraviolet radiation, X-rays, and gamma rays. Radio waves have the longest wave length due to its low frequency. Radio waves are also part of the electromagnetic spectrums subsection known as radio frequency or RF. The radio frequency spectrum shows the radio wave length and its frequency in Hertz. The spectrum includes extremely low frequencies of 3 to 30 Hz with a wave length of 100,000 km to 10,000 km and extremely high frequencies of 30 to 300 GHz with a wave length of 10 mm to 1 mm (Wikipedia, 2006).
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Radio Bands
In Canada “Industry Canada” regulates radio frequencies and who is allowed to use which one (Industry Canada, 2007). In the USA the Federal Communication Commission or the FCC carries out this role (Brain, 2006). These organizations assign different sections of frequencies, called bands, for different uses. Some well know bands are, AM radio which has frequencies 535 KHz to 1.7 MHz, television stations 2 to 6 with frequencies 54 MHz to 88 MHz, FM radio which has frequencies 88 MHz to 108 MHz, and television stations 7 to 13 with frequencies 174 MHz to 220 MHz. There is a band assigned for every type of radio broadcasting device such as a baby monitor or a garage door opener. The higher the frequency is the more data the signal can carry (Brain, 2006). One major band is the Wi-Fi or wireless local area network (WLAN) which spans 2.400 MHz to 2.487 MHz. and is for universal use, by an international agreement (Wikipedia, 2006).
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Wifi
Wi-Fi is the transfer of radio waves from one antenna to another for use by computer devices. It has changed how the world uses computers. It allows internet and computer to computer sharing without long wires connecting everyone’s computers. Wi-Fi is becoming steadily more popular due to the ease of use and convenience. Almost all Wi-Fi connections now use routers (also known as access points) to send the wireless signal to the wireless devices.
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Routers
A router is simply a computer with the specific job of directing information. Routers are used to send information to and from computers which are not directly connected to each other. This is done through one or more networks. There are two types of routers, wired and wireless. The only difference between wireless and wired, as is suggested by the name, is the wires. A wireless router allows a connection to a network when a wire is not an option. This is useful for networks with multiple computers, laptops, internet hot spots, etc. The wireless signal is radio waves of either 2.4 MHz or 5.0 MHz depending on the version of Wi-Fi being used.
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Types of Wifi
There are several different types of Wi-Fi to choose from when deciding on a router. The naming of each type of Wi-Fi is from the Institute of Electrical and Electronics Engineers or the IEEE. The original Wi-Fi is know as 802.11 and had a transfer rate of 1 megabits per second or Mbps. The next version was the first commercially available and was know as 802.11b which has a transfer rate of 11 Mbps. This version is still very commonly used. The third version was 802.11g. It has a maximum speed of 54 Mbps and is a very stable version. This is quickly becoming the most prominent version. There has recently been a new version of Wi-Fi know as draft N. It has not yet been standardized and is still rather unstable.
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Antennas
An antenna is simply the device which sends and receives the radio waves which are used by the computer or router. There are two types of antennas, omni directional, and directional. With an omni-directional antenna the signal is sent in all directions at equal strength. A directional is just the opposite. With a directional antenna the signal is sent in a specific direction with all of the signal strength focused in that direction. The omni directional antenna is good for home networks and networks with more than one computer distributed around the router. A directional antenna is good for sending wireless to one computer because the signal is much stronger in the one direction. One measurement of signal strength is dBm. dBm is decibels relative to 1 millwatt. Another way to say that is whether the signal is stronger or weaker than 1 mW. The average dBm for a wireless network is -60 to -80 dBm (Wikipedia, 2006).
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Increase Signal Strength
For most consumer routers the antenna is very small. This is useful because this makes the router small and compact but in turn the small size limits the signal strength possible to be broadcasts. The most efficient means to increase your signal is to employ a new directional antenna. If this is not an option for the specific person then they should begin to look at the routers physical placement. There are two main types of interference, direct and indirect. Direct interference is from other routers. Indirect interference is from other devices which emit radio waves such as cordless phones and baby monitors. Indirect interference is also caused by devices which emit microwaves, the next frequency on the electromagnetic spectrum. To prevent interference from your microwave keep the router out of its direct line of sight. Another way to increase the routers signal is to place the router on a table or desk, away from the ground. If these ideas still don’t increase the Wi-Fi signal enough, then you should look at ground planes. A good ground plane is an electrically conductive surface. This will redirect the radio waves in the direction you want (Binary Wolf, 2006).
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