What Is Dual Band Wireless?by Stephen Byron Cooper
Dual band wireless equipment operate over two different frequencies. The Wi-Fi standards originally defined two different, incompatible systems, one offering high performance with expensive equipment, the other sacrificing performance to achieve affordability. Since these two standards were published in 1999, the standards have evolved to try to reconcile the two different systems, which use different frequencies. Dual band wireless equipment achieves this goal.
Wireless networks send data out over radio waves. The wireless transmitter first generates a standard carrier wave. The wireless network adapter merges a segment of data from the computer, represented as a square wave, with the carrier wave. This is called modulation. When people talk about the frequency of Wi-Fi networks, they are referring to the frequency of the carrier wave.
The frequency of a radio wave is the rate at which waves are generated. It describes both the number of waves per second and the length of the wave. A higher frequency means more waves per second, and those waves are thinner and travel faster. As each wave carries data in a Wi-Fi network, the higher the frequency, the faster data can be transferred. Frequency is expressed in Hertz, which is abbreviated to Hz. Wi-Fi networks deal with GigaHertz, which is abbreviated to GHz. A GigaHertz is a thousand million Hertz.
Wi-Fi systems follow one of the standards published by the 802.11 working group of the Institute of Electrical and Electronics Engineers. All of their standards are labelled with the 802.11 code followed by a letter to distinguish one from the other. The first two standards, published by the working group in 1999 were 802.11a and 802.11b. The 802.11a standard produced an efficient Wi-Fi network suitable for businesses. It used a 5 GHz frequency. This frequency was expensive to generate, however, and so the working group used a 2.4 GHz frequency for the 802.11b standards. This produced a Wi-Fi network within the price range of the home consumer. So two frequencies were in operation and the two systems were incompatible. Equipment made to operate on a 2.4 GHz frequency could not communicate with equipment using a 5 GHz frequency. A dual band wireless router operates on both frequencies.
The price of electronics has reduced considerably since 1999. This makes the latest home Wi-Fi standards capable of operating on the 5 GHz frequency at an affordable price. However, an intermediate standard produced by the IEEE in 2003, 802.11g, used the 2.4 GHz frequency, to enable compatibility with 802.11b. The IEEE insisted that its latest standard, 802.11n, could communicate with equipment following 802.11b and 802.11g standards. So 802.11n operates on both the 5 GHz and 2.4 GHz frequencies. This requires a dual band wireless router.
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