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To setup a wireless network you need two main pieces of hardware.
Wireless Router. A wireless router literally routs information to various components on a wireless network. Much like a wired router, the wireless kind is capable of communication with computers, printers, cable modems, and other peripherals and equipment. Most wireless routers are capable of communicating using the 802.11b, 802.11g, and 802.11n technology standards.
Wireless Network Adapter. Like a wired Network Interface Card (NIC), a wireless network adapter allows you computer to communicate with the wireless router. Wireless Network Adapters look like NICs except they usually have an antenna sticking out the back for receiving and transmitting data. Most modern laptops have wireless capabilities built in. If not, you will need to purchase a wireless network adapter specially designed for laptop computers.

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The WiFi or 802.11 networking standard was never designed for long distance networking. The typical wireless router and network adapter is only capable of communicating with other wireless equipment at a distance of about 90-100 feet indoors and up to 300 feet outdoors.
If you live in a particularly large home or if you own a home that is not conducive to wireless networks because of radio interference, you may need to extend your 802.11 WiFi signal using a WiFi long distance antenna or booster.