Are you sick of dead spots with no reception?
The key to solving weak reception is more signal strength with less noise. 802.11b at 11Mbps and 802.11g at 54Mbps (Mbps or megabits per second, a measure of bandwidth) and 802.11n are speeds which depend on your signal strength and noise level of your wireless card and wireless system. Ideally, you want the noise level (measured in dBm) to be as low as possible. Cordless phones and microwaves are common culprits for increasing the noise level.
Wireless access points (AP) normally have a built in Wi-Fi antenna that radiates a signal equally well in all directions over distances of 250-300 feet (76-91 meters). These antennas are usually referred to as omni-directional. An omni-directional antenna is an antenna that produces a constant field strength in azimuth (horizontal), but that can have a directional radiation pattern in elevation (vertical). It differs from an isotropic antenna in that an isotropic antenna produces a constant field strength in both azimuth and elevation. When the AP is located in the center of a building or a home, an omni-directional antenna helps to reach all rooms of that structure.
An omni-directional antenna can be weak over longer distances from interference and because its signaling power radiates in all directions. As it continues to travel away from its source, the signal strength begins to grow weaker. The farther the signal travels, the weaker it becomes; until finally it looses its integrity. This is referred to as attenuation. Sometimes, it is better to replace the AP's built-in antenna(s) with a stronger omni-directional antenna and/or a focused yagi or waveguide. It's a good idea to purchase AP's with removable antennas.
Using an after market external omni-directional antenna that is stronger (around 5dB) than the AP's built in antenna (around 2dB) can produce a stronger signal and better network performance. A possible problem with the less expensive omni-directional antennas is that they come with a low quality cable. Due to the inferior cable, there is a very high amount of loss of the radio signal. You can minimize loss by using the appropriate type of quality microwave cable in the minimum length required to make the connection.
Adding a ground plane (an electrically conductive surface that serves as the near-field reflection point for an antenna) can help boost a signal. A simulated ground plane may be made from a large metal sheet or several wires or rods radiating from the base of the antenna.
A more costly antenna that is too strong, however, raises security concerns. Strong omni-directional Wi-Fi signals are radiated to a greater distance into neighboring areas where the signals can be readily detected and viewed. Donít place the antenna near a window, as the glass does not block the signal. Place your antenna in the center of the area you want covered in order to limit how much the signal can reach areas outside the coverage area. Adding commercially available inexpensive antenna reflectors (photo) or diy parabolic reflectors to an omni-directional antenna can help direct a signal in the preferred direction. These reflectors don't require pigtails & don't have matching (swr) problems.
A somewhat safer choice for increased range is to use a high gain directional antenna that will send a strong signal in a specific direction. The focused signal will allow better control by aiming the signal towards the desired location.
Gain, or how well the antenna focuses a signal of an antenna, is primarily proportional to size - more gain requires a bigger antenna. The size that matters is the aperture, the effective electrical capture area of the antenna. The larger the aperture the narrower the beamwidth, so that more energy is concentrated in the desired direction, yielding more gain. A larger aperture providing more gain can be created by building a horn antenna. Horn antennas are generally fed by a waveguide such as the circular coffee can antenna or perhaps a rectangular shaped waveguide. See the horn antenna designer.
Fixing dead spots in a building or a home is ideally done in conjunction with an AP with two external antennas (diversity mode, when the radio monitors the signal from both antennas and automatically uses the one with the best signal). First try setting one antenna vertically for the first floor, and the other horizontally, for an upper or lower floor. If the problem still exists, try replacing one of the antennas with a directional antenna. This is preferable because it may allow the built in omni-directional antenna to remain operational while the yagi or waveguide cantenna is focused on the problem area. It's likely you will lose the omni-directional multipath characteristics of your access point, but in exchange you will be able to direct signals to a specific area as well as gain signal strength over the factory dipole antennas. There's 3rd party software here and here that will allow one antenna to send and the other antenna to receive. In many versions of Linksys routers, the Antenna Selection option is located within the Advanced Wireless Settings tab. You set your Antenna Selection option to use either the left or right antenna.
Consider a repeater (Belkin) as another method to extend the range of your wireless network. A repeater, or wireless range extender, increases the range of a single wireless LAN by extending the LAN's wireless signal. A repeater will pick up the signal from your current wireless access point, and rebroadcast it to your clients, and vice versa. Some APs can be configured to function as repeaters. Check the manufacturer's specifications to see if it is possible. Find out if the repeater is compatible with your existing network before you buy.
In order to set up a repeater, (Linksys) carry a Wi-Fi-equipped laptop toward the area to which you'd like to extend Wi-Fi coverage. Walk to where you are seeing 20 to 50 percent signal strength. This is where you want to plug in the repeater's power cord. The repeater should begin interoperating with the router and effectively extend the reach of your home network.
Know that when you add a repeater, (Netgear) you cut your maximum bandwidth in half. A repeater must receive and retransmit each frame on the same RF channel, which effectively doubles the number of frames that are sent. For example, a 802.11g network consisting of a router and a repeater will have a maximum speed of 27Mbps.
Take a look at Luxul Range Extenders which are high performance products featuring quality high gain antennas. Linksys offers the Wireless-G Range Expander which does not need to be connected to the network by a data cable. See Using Range Expanderís and/or High-Gain Antennas for more suggestions.
Turn Your Older Linksys Router Into a Range-Boosting Wi-Fi Repeater (scroll down the page)
Check Signal Strength & Align Your Antenna For Best Coverage
The Wi-Spy Spectrum Analyzer, is the world's smallest 2.4 GHz spectrum analyzer, and has been designed specifically for troubleshooting and analyzing Wi-Fi networks. It shows the signal strength for all Wi-Fi networks as well as Bluetooth, 2.4 GHz cordless phones, microwaves, Zigbee, and all other 2.4 GHz transmitters. At a glance you can see what Wi-Fi channels are quiet and what channels you should avoid if possible. This makes it easy to pick a quiet channel for your access point instead of picking your favorite number between 1 and 11. This device is great for spotting any RF activity that could be interfering with your wireless network. Compared to a dedicated full featured spectrum analyzer, it is relatively inexpensive, small, and easy enough to use so that it can help be a major step towards compensating or eliminating interference with your WLAN.
Wi-Spy Spectrum Analyzer
NetStumbler is software that senses the coverage of an wireless access point's (AP) transmission. NetStumbler includes a high-resolution field strength and signal-to-noise ratio display. With a laptop running NetStumbler, you can walk around and find weak spots and dead spots in an AP's coverage, as well as determine the limits of the AP's useful range.
NetStumbler is also useful in testing the relative effectiveness of Wi-Fi antennas. Place a laptop running NetStumbler in a fixed position, and then aim the AP's antennas at it. If the antennas are at the same distance from the laptop, NetStumbler's readings will reflect how well the antennas compare to one another. Mac people can use iStumbler, MacStumbler and KisMac.
NSSpyglass will alert you to netstumblers and wardrivers in the area looking for access points with NetStumbler. NSSpyglass requires an association with a Linksys Access Point (computer running NSSpyglass must have the SSID set to the same SSID as the Linksys Access Point).
An alternative method is to use ping to measure latency (time) and orient your antenna for the smallest time. For example, to run ping in Windows XP, click START > ALL PROGRAMS > ACCESSORIES > COMMAND PROMPT. A window will open with a C: prompt. At the prompt, type something like:
ping 192.168.1.1 -t
The IP address is typically that of your AP. The command will run ping indefinitely until you use CNTRL C to terminate the ping. As you view the time field, orient your antenna until you see the smallest time.
A DIY field strength meter for 2.4Ghz wireless LAN uses a voltmeter, a diode from a solid state microwave leakage detector and a 2-element quad antenna oriented in a diamond configuration so it should be effective for both horizontal and vertically polarized signals.