# `2.4 GHz Antenna`

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 Its kind of funny actually. Makers of cordless phones often advertise these devices with the main feature being "operates at 900 MHz". That is completely irrelevant from an operational or end-user viewpoint. What does specifying the frequency in GigaHertz or MegaHertz mean? A 2.4 GHz antenna or system is simply a device that transmits and receives at the frequency 2.4 GHz. All devices are required to operate in a narrow frequency band. Wireless routers are forced (by government regulation) to work at 2.4 GHz. If the government had said they have to work at 2.9 GHz or 1.3 GHz, it would not have mattered at all. The wireless propagation environment is different for 2.4 GHz or 1 GHz, but for home personal wireless communications it would not matter significantly. The only thing 2.4 GHz really tells you is that the wavelength is c/f = (3e8 m/s)/(2.4e9 1/s) = 0.125 meters = 4.92 inches When you plug in your home wireless router, the antennas will probably be dipole antennas, because they receive information uniformly in the horizontal plane, and the router won't know where your computer is located. Since dipole antennas work great when they are a half-wavelength long, you could guess the antennas should be about 2.5 inches long, as is roughly the case if you look at your typical router: There are two antennas primarily for diversity reception. If you are trying to get free wireless internet, you could look around for a high-gain directional antenna at 2.4 GHz. To get this to work, you'll need to attach your router to a high gain antenna that is pointed towards a McDonalds or somewhere that is giving out free Wi-Fi from their wireless LAN (or steal it from one of your neighbors who is not using encryption - by the way, its worth taking the few minutes required and set up your routers encryption for this reason). A high gain antenna is simply an antenna that has a very directional radiation pattern, in that it receives energy most strongly from particular directions and suppresses them from other directions. Bluetooth devices also use the 2.4 GHz band, in addition to some cordless phones and radio controlled toys. The IEEE 802.11 wireless standard specifies WLAN computer communication at 2.4 GHz.

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