If you are setting up a wireless home network, you should know that you can maximize your network's performance by replacing the WiFi antenna. While this is not necessary in the majority of cases, if you are having trouble getting access to the network throughout your home, or if you just can't strategically place your router or access point because no matter where you put it, the signal strength is weak in places, replacing the WiFi antenna may be the solution you've been looking for.
Built-In WiFi Antennas
Most access points and routers contain built-in omnidirectional antennas. These antennas send signals out equally well in all directions. This makes router or access point set up easy, since when it is placed in the center of the home, and wireless devices are located throughout the rooms, an omnidirectional antenna ensures that signals are sent to all corners of the house.
However, while the omnidirectional antenna built-in to your router or access point makes setup easy, it may not be the most effective antennas for your wireless home network. The built-in antenna may have trouble reaching all places in your house where network service is required.
Replacement Antennas
Built-in omnidirectional antennas can have trouble sending signals for long distances because power must be expended in all directions. This means there is less power left over for long distance coverage.
To address this problem, some manufacturers sell external omnidirectional antennas that are significantly stronger than the built-in antennas. This increases the distance that the routers and access points can service. This will in turn increase network performance.
But there are also security concerns for wireless antennas that are too strong. The stronger your omnidirectional signal, the more likely it is to bleed outside the house, where signals can be snooped and exploited.
To deal with this concern, you can replace your omnidirectional antenna with a high gain directional antenna. This will send a strong signal in a particular direction of your choosing. Since the signal is focused, it can be better controlled by aiming it at the area of your home where wireless devices are located.
Many routers have an external antenna jack that allows you to connecting the new antenna. Consult the router product documentation for details.
Selecting a WiFi antenna
The single most important thing you can do to extend the range of your 802.11 system is to install an external antenna with some good gain and directional or omni-directional qualities. WiFi is simply a radio, which is used for computer. You can think of your antenna as the “speaker system” of your WiFi card. Get a bigger antenna; your WiFi will go a lot further. However, don't install a speaker on your wifi system or your range will be horrible!
Directional Antennas 
Directional antennas are used for Point-to-Point or sometimes for Multi-Point systems depending on the setup. If you are trying to go from one location (say for instance your router), to another location, this is the type of antenna we recommend.
Omni-Directional
This is the common “Base” antenna used for Point-to-Multi-Point or can be an omni-directional antenna for your car. An Omni-Directional antenna would serve as your main antenna to distribute the signal to other computers or devices (such as wireless printers, PDAs, etc) in your workgroup. You can use 2 Omni-Directional antennas for a point to point system, but this is usually not recommended because there is no real point to distributing your signal all over the place when you only want to going from point A to point B.
Point-to-Point
Point-to-Point systems usually involve 2 different wireless points, or building to building wireless connections. But there are exceptions to every rule. If the access point is across a long valley and the owner of the system wishes to share the connection with multiple users on the other side of the valley. This would be a point to Multi-Point system but using directional antennas.
Home
Home antennas are always the easiest types of antennas to purchase and take the least amount of effort in choosing and installing. In most circumstances, only one antenna is needed on the remote computer. We recommend putting any external antenna on the remote computer, simply because if you install it on your router and don’t plan on setting up security, it will provide less signal strength outside of your home and your system will be less prone to hackers. If you have a multi-story home or a very large house, you may have to install antennas on every computer to get the range or bandwidth required. Every wall that you have to penetrate will decrease the signal strength of your system.
Office
Office antennas are pretty straight forward. If you want to run a network system inside of your office building and don’t want to run cables all over the place, first, purchase a good wireless card. However, this can get a little complex if the office is split between 2 different points or if the office is really large or on multiple stories of a building.
Mobile WiFi antennas
Why would anyone want WiFi in their car? Well, there are a lot of truck-stops and RV parks around the country now that offer wireless access. In fact, many public high speed wireless networks can be accessed directly from your car, truck, or RV. There is also something called WarDriving which is where bad people drive around neighborhoods and get their high-speed access for free.
Yagi Antennas
Yagi antennas were the design of two Japanese people, Hidetsugu Yagi and Shintaro Uda, and are sometimes referred to as Yagi-Uda antennas. They were originally designed for radio, but are now also used for 802.11 systems. These antennas are typically very directional and are used for point to point, or to extend the range of a point to multi-point system. We highly recommend using the RadioLabs 14 or 16 element weatherproof Yagi antenna if you want to install your system outside. They have excellent signal strength and in the right circumstances can communicate for miles!
Backfire antennas - The backfire is a small directional antenna with excellent gain. They look similar to a parabolic dish, but the gain isn't as high. We highly recommend Backfire antennas for point to point or point to multipoint systems because of the excellent gain and the good noise figures. We offer a backfire antenna with 15 dBi of Gain!! This is excellent considering the antenna is only 10 inches diameter. Almost invisible!!
Parabolic or dish antennas
This is where the real power is! Parabolic dish antennas put out tremendous gain but are a little hard to point and make a connection with. As the gain of an antenna increases, the antenna’s radiation pattern decreases until you have a very little window to point or aim your dish correctly. Dish antennas are almost always used for a point to point system for long haul systems. The Parabolic Dish antennas work by focusing the power to a central point and beaming the radio’s signal to a specific area, kind of like the adjustable reflector on a flashlight. These antennas are highly focused and are the perfect tool if you want to send your signal a very long distance.
Gain Considerations
The gain you will require for each individual WiFi antenna system will dependant on any direct objects in your path, the distance you must cover and the individual wifi cards. These all must be taken into consideration before choosing the proper antenna system. If our calculator is too difficult to use, please feel free to contact us for information.
Interference
As with all radio systems, interference is always a problem. If you are listening to an AM radio and you hear static, this is interference. The same thing applies to WiFi systems, however not to such a large degree. Things that cause interference with WiFi systems are Microwave ovens, certain lighting systems, other 802.11 access points or systems, microwave transmitters, even high speed processors for computers can cause interference for 802.11 systems. All these problems must be isolated before you can expect any significant range out of your system. If you need help, please don't be afraid to ask us. Afterall, WiFi is our business.
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