Extend range of wireless LAN part 1 (introduction)

      Reference from chip magazine. Basically, Wireless Fidelity (Wi-Fi) is a wave / radio frequency used and developed for computer. Like all radio system, the main problem often faced is signal interference. If you hear static sound in the radio, this is an indication of a disturbance.
      Same thing applies to Wi-Fi. things that may interfere Wi-Fi signal is the wave of microwave oven, another Access Point, or even the high speed of the computer processor. The best solution that you can do to extend the range of the WI-Fi signal and overcome interference of radio waves is to add an external antenna to get a system with good capabilities to received signal. either that often confuse users is how to chose Wi-Fi antenna accordingly.
      This is necessary knowledge to chose Wi-Fi antenna :

Definition of frequency and wave

       Frequency and wavelength are interconnected. if the frequency increases, the wavelength decreases and vice versa.
       Frequency: is the amount for which an oscillating radio signal moves from positive to negative. wavelength: the full cycle of the oscillation the radio signal. 
      Wavelength size usually are represented in metric units (meters, centimeters, and so on). while the frequency is a count of the number of waves that occur during a specified time, usually in units per second, which is denoted as Hertz (Hz).

       





Avoid microwave that uses the same frequency bands with WI-Fi, avoid placing the device in close proximity.


Standardization of Wi-Fi 

       Before discussing the antenna, it helps us review a little about the standardization of Wi-Fi.
       Wi-Fi 802.11a standard operates in the 5 GHz frequency range, which has a much faster transfer rate compared to the 802.11b standard. Unfortunately, this frequency has a weakness, namely because of the longer range signals that reach elusive. This led to high investment costs antenna. in addition, the provisions of international regulations also restrict the use of these frequencies. The problem is what causes the standard Wi-Fi 802.11a Wireless networks are rarely used.
      Meanwhile, 802.11b and 802.11g standards use the same frequency that is 2.4 GHz with a wavelength of about 12 cm. Because the wavelength is relatively short, it is necessary that the antenna design is relatively smaller. This makes the 2.4 GHz frequency is used as the standard Wi-Fi internationally.
      The interesting thing from the standard "g" is the compatibility with 802.11b. which means that the product has a standard "b" can be connected directly to a standard "g" without the need to upgrade hardware.

Wi-Fi Channel
       
       Wi-Fi consists of 14 channels that have been agreed internationally. Channels used in each country is different. Wi-Fi in the table below shows each channel and the frequency used by countries in the world (of Southeast Asia including Indonesia, using channel 1 to channel 11 as a standard Wi-Fi). This scheme is still overlapping with channel radio technology that exists today. It is defined by the IEEE standard, for example, channel 6 based in 2.437GHZ, but extending in both directions by 11 MHz (0.011 GHz). this means that the channel 6 using frequency 2.426 GHz.

 

 












will continue on the second part.