How to choose the Wi-Fi antenna Detail Guide

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After going through the antenna section of the forum, I've realized that many topic's concern the same subject: What antenna choose? What is the best dish? Etc .. 
So I thought that it might be useful, while avoiding many issues discussed again. 
(I should point out that this topic is a "mix" of all that has been said in this section, and information found on the net)

I: A few (minor) Information on the IEEE (Institute of Electrical and Electronics Engineers) or wireless
How to choose the Wi-Fi antenna Detail Guide
This can be classified into 4 parts:
-The personal wireless networks: Wireless Personal Area Network (WPAN)
-The Wireless LANs: Wireless Local Area Network (WLAN)
-The metropolitan wireless networks: Wireless Metropolitan Area Network ( WMAN)
-The large wireless networks: Wireless WAN (WWAN) Also distinque 3 IEEE standards (For the 2.4GHz frequency): -802.11b: Theoretical flow rate 11Mb / s -802.11g: Theoretical flow rate 54Mb / s -802.11 n: Theoretical flow rate 270MB / s Note: Theoretical do not mean real. The WLAN uses the frequency range of 2.4 GHz. Incidentally, the same frequency as our dear microwave ovens (If you find offline whenever you use the microwave, do not look any further, it is able to blur your connection to the AP (yet it should not emit waves outside the home? Anyway, that 's another story ..)) There are many things to say about the wireless, but that's not the point. II: Different kinds of antennas for different applications Before asking "What's the best dish?" it would be better to target the use that we will make. In fact, each type of antenna has a function and a specific utilitée. II.1: "How many I will have to reach with this one" The range depends on an antenna's gain (in dBi), but also the power of the equipment (antenna + card) which is opposite. Meanwhile, many people forget that other factors must be taken into account, such as barriers, the thickness of materials, materials in themselves, distance, humidity (we will see better results in dry weather that raining temp, just as it will be difficult to pass through a crowd with our wave) the wiring used and the sensibilitée your wireless card, to name a few. This is why it is impossible to determine a view eye the scope that you provide your antenna. II.2 "! Me I have a DirectOmniSectonielle 512dBi antenna of death" primarily We differentiate 3 large families of antennas: 1_L'antenne Omni: In rod, they can cover a horizontal distance of 360 °. However, their vertical action radius is small: inversely proportional to their power. Indoors, omnidirectional antennas are often the best choice. These antennas often do not cost very expensive. For imaging, I allow myself to quote Calc1neur "The Omni shines a bit like a candle, its scope is small against it captures (lights) networks all around 360 ° 2_L'antenne Directional: Their purpose is to create links between specific points:. between 2 houses, for example can be found in several types: panel, yagi, dish (grid ...) Their scattering angle is small (15 to. 60 °), inversely proportional to their power and usually the same vertically and horizontally. These antennas will therefore require more fine-tuning, and know where our target. For imaging, I allows me (encors) quoted Calc1neur " The Directional radiates it as a powerful car headlight, and picks (lights) so ideally the networks that are in its beam, even if they are quite distant. "3_L'antenne Sector: They can cover a angle of 60 to 120 °. The power of the antenna is focused on the area to be covered. Furthermore, the vertical angle is relatively large. This feature makes them virtually indispensable on rough terrain. As the vertical axis is adjustable, it is thus possible to adapt to the topography. They therefore represent a good compromise between Omni and Directional. I will end with one last quote Calc1neur (Copyrightforces) "It would not come to mind to illuminate your room with a car headlight or driving at night by candlelight ... well it's the same with wifi antennas! "As you can see, each antenna has its function. III_" I chose my antenna! And now ..? "Then now you puts you in the *** (nose) and you make the plane! Seriously though, remains the wiring. As with anything, it is best to minimize the length of / cables used. In fact, underestimating the signal loss caused by the length, we end up losing the gain offered by our channel! Simply connect a cable to connect the antenna to your key causes losses (Quality connectors, etc ..) Over the cable has a large section and the losses will be limited. The low loss cable (diam. 5.4 mm) generally appropriate for a length up to 4 meters, especially since it is much more flexible than the very low loss cable. In addition, the very low loss cable (diam. 10.3 mmm) is strongly advised. Caution also to some suppliers who do not hesitate to sell you the cable "low loss" with "low loss". Basically, the more the diameter of your cable will be, the more signal loss will be small. PS: Attention has to check the connectors on your card / antenna before you buy! (The Wi-Fi antennas are usually equipped with SMA connectors RP-SMA or N depending on the manufacturer.) Here, I think the key was said. I undertake to have days this topic (More details on the types of antennas such as panel, Satellite, Yagi etc. ..), thank you to inform me of any information that might be missed

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