by Evan H. Shu, FAIA
Does it feel like the air is extra "charged" these days? The air waves are buzzing with communications from cellular telephones, remote control devices, and global positioning devices. Our digital world is being transformed by these technologies and, most recently, by wireless networks.
In many cities, you can go to some public place, open a suitably equipped laptop, and log into the Internet without physically plugging into anything. These wireless fidelity ("Wi-Fi") broadband connections are not only in computer stores but in coffee shops, public libraries, bookstores, convention centers, and hotels.
The number of these free networks is growing rapidly. You can check out availability yourself at such sites as "Wi-Fi Free Spot," which has listings for cities all over the world. These free network locations ("hot spots") are quickly growing in number because the cost of creating one is so inexpensive. We recently set up our own office Wi-Fi network for under $50.
What Is Wi-Fi?
Think of Wi-Fi as a little ham-radio station, operating in the 2.4-gigahertz band. This is 2,400 megahertz, in contrast to a typical FM radio station which operates at around 100 megahertz. Cell phones operate at 824 to 849; global positioning devices operate at 1,227 to 1,575 megahertz.
A key difference between Wi-Fi and a typical radio station is that the communication is two way, somewhat like in a walkie-talkie device. In ordinary cell phone conversations, two frequencies are used, one to talk and one to receive, so you can have overlapping speech.
A walkie-talkie or "direct-connect" device uses a single frequency with a push-button-to-talk and release-to-listen feature that tells the device whether to send or receive. In the same way, a Wi-Fi communication sends and receives, but not at the same time (although the "push-to-talk" all happens invisibly and at lightning speed). >>>
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Cafes and libraries are often wireless Internet "hot spots."
Photo: David Owen
Wireless networking (Wi-Fi) operates in the 2.4GHz frequency range of the electromagnetic spectrum.
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