Troubleshooting Wi-Fi Problems
Performance and stability of wireless / WiFi/ 802.11 networks:
Solving wireless problems can be tricky, but it's not rocket science. There are a few basic concepts to understand, but your success most likely will depend on your own observations and detective skills. In the end, the majority of problems can be traced to RF interference, misdirected antennas and "dead spots". Four things to keep in mind as you tackle a WiFi-related problem:
1. It is most likely caused by interference, the existence of "dead spots", or poor reception that can be corrected by better locating/aligning an antenna.
2. The beacon strength of an access point is not a measure of the performance of your wireless network. Nor do you want to necessary associate with the access point with the strongest beacon signal.
3. In 802.11 b/g you have a choice of 14 channels (actually, 11 channels in North America) – where each channel is a range of frequencies. There is tremendous overlap among adjacent channels (take a quick look at the image at the bottom of this page). The reason why it's important to make note of the overlap is that a wireless device that transmits in the frequency range of channel 1 not only interferes with channel 1 but probably also is wrecking havoc on channels 2, 3, etc…
4. When interference is the cause of poor performance, then the most common solution is to reconfigure your access point to use a different channel. In certain situations you may need to track down the source of interference, but more often than not it will be coming from a source or location you have no control over. So, the simplest "fix" is to identify a channel that isn't subject to interference and reconfigure your wireless network to use that channel.
To get a jump-start in troubleshooting interference-related problems that degrade the performance of your WiFi network, then check-out some of ourlow-cost wireless diagnostic tools…
In most environments the presence of non-802.11 devices dwarfs the number of 802.11 devices. These non-802.11 devices could include microwave ovens, cordless phones, Bluetooth devices, wireless video cameras, wireless security devices, outdoor microwave links, wireless game controllers, Zigbee devices, fluorescent lights, motion detectors, automation sensors, WiMAX, and so on. Even bad electrical connections can cause broad RF spectrum emissions. Non-802.11 types of interference can significantly impact the performance of a wireless network by causing a loss of data throughput. In addition they can cause secondary effects such as rate back-off, in which retransmissions caused by interference trick 802.11 devices into thinking that they should use lower data rates for backward compatibility with older/slower 802.11 devices.
A 2.4 GHz spectrum analyzer is the tool of choice for detecting and identifying sources of RF interference.
Spectrum analyzers are a basic tool used for observing radio frequency (RF) signals – they give you a better picture of the RF environment to help identify and find devices interfering with your Wireless LAN (WLAN). Typically they’ll employ a 2-dimensional display where the vertical axis (Y-axis) represents the magnitude of a signal and the horizontal axis (X-axis) represents the frequency of a signal. Dedicated hardware spectrum analyzers can run into the tens of thousands of dollars (they employ many arrays of analog-to-digital converters). Recently, PC-based analyzers have appeared on the market. Check-out some of ourlow-cost wireless diagnostic tools that help you detect the presence of interfering devices and then choose the best channel for your wireless network.
Nuts About Nets develops innovative diagnostic tools for installing, optimizing and troubleshooting 802.11 (WiFi) wireless networks. Our tools include RF spectrum analyzers, 802.11 channel analyzers, 2.4x and 5.x GHz channel / signal generators, and 802.11 packet injectors. Our low-cost products offer an unbeatable value — they are easy to use, sensitive, accurate and a fraction of the cost of proprietary hardware test equipment.