Wi-Fi wireless networks have grown in popularity in recent years and are found ubiquitously in the economy, industry and at home. Wi-Fi networks in the 2.4-GHz Industrial, Scientific and Medical (ISM) band - a public that is not licensed by the FCC. Many types of wireless devices compete with Sky in the 2.4 GHz ISM band - and this leads disorders that adversely affects the performance of a wireless network. A 2.4-GHz spectrum analyzer is theTool of choice for the detection and identification of interference sources and provision of information, the optimal configuration of a Wi-Fi network allows.
Overview
With wireless systems it is very difficult to predict the propagation of radio waves and the presence of interfering signals without the use of test equipment. Radio waves do not travel the same distance in all directions - instead of walls, doors, elevator shafts, people and other obstacles offer varyingDegree of damping, which the radio frequency (RF) radiation that cause irregular and unpredictable. To ensure optimum reliability and throughput for your Wi-Fi to (802.11) wireless network it is necessary to recognize and identify sources of interference that may negatively on his performance.
There are a variety of electronic devices, the RF transmission of energy in the airspace. Wi-Fi (802.11 b / g) operates in the 2.4 GHz Industrial, Scientific, and Medical(ISM) band. This particular frequency range (2.401 GHz to 2.473GHz) is public and their use does not require approval by the FCC. As a result of this band tends to get rather full - not only with 802.11 devices, but also microwave ovens, Bluetooth devices, cordless phones, baby monitors, audio / video transmitters, wireless cameras, etc.
Optimize Professional installers of wireless computer networks to try to reach their customers Wi-Fi network a strategic choice of aSubset of the 2.4-GHz band for use by their wireless network devices. The 2.4-GHz range from 2.401 to 2.473 GHz is divided into 11 each, 22 MHz channels. Note that 2.473GHz - 2.401GHz = 72 MHz, 11 times 22 MHz or 242 MHz. So, how fit is 242 MHz to 72 MHz? Answer - the channels overlap. An installer is the wireless router or access point (AP) be configured to channel 6, and then uses all data communication will occur over the range of frequencies associated withChannel 6 (ie 2.426 GHz - 2.448 GHz). But if other wireless devices (802.11 or non-802, 11) are also transmitting on this frequency range will suffer from your wireless network among them. So, if a wireless network or troubleshooting a weak performance is, it is important that a channel that is not subject to interference from other select devices - that is, you do not want your wireless network with other devices provide the same range of competingFrequencies.
Wi-Fi Diagnostics tool
There are two categories or types of tools for helping you choose the best Wi-Fi channel for your wireless network available - WiFi Scanner (ie, 802.11 discovery tools), and 2.4 GHz spectrum analyzers :
Wi-Fi scanner, or 802.11 (WLAN) discovery utility. The best known in this category is NetStumbler (http://www.netstumbler.com/). The discovery tool is the Service Set Identifier (SSID) report for each accessPoint (AP) it detects, along with the channel used by the AP. This works is that about every 100 ms, an AP sends an "I'm here" beacon - and the discovery tool (on your laptop, and with its 802.11 wireless adapter) takes the beacon and adds the SSID to its list. In addition, the discovery may Utility Report SNR (signal-to-noise) ratio for each AP, which as an indication of how close the AP is your current location. Although thisuseful information, it does not tell you what not to employ-802.11-devices, and, as the AP. This is could be your laptop sitting next to a microwave, send all types of RF energy into the room, and the discovery tool would be unaware of its existence. The Discovery program knows only about 802.11 devices - devices which transmit RF energy to the 802.11 protocol - and can not see, not-802, 11 transfers. Here is an analogy - you are in a major isAuditorium and you hear someone yell across the room sometimes, "Hello, I'm Joe!". Joe is an Access Point, and he occasionally sends a signal to leave, who's out there know that he is there. It could be that Joe is really busy and talk to many people, or he can be with him. Or there are a lot of noise in the auditorium, it would be difficult to carry on a conversation with Joe from a distance. The discovery tool can not help you with that - just listenJoe's occasional beacon "Hello, I'm Joe!".
2.4 GHz Spectrum Analyzer. This is the tool of choice for the detection and identification of sources of RF interference. Spectrum Analyzer is a fundamental tool for monitoring radio frequency (RF) signals are used - they give you a better picture of the RF environment to help identify and find devices interfering with your wireless LAN (WLAN). Typically they are based on a 2-dimensional representation, where the vertical axis (Y axis)represents the magnitude of a signal and the horizontal axis (X axis) is the frequency of a signal. Dedicated hardware spectrum analyzers can be in the tens of thousands of U.S. dollars they get (employ many arrays of analog-digital converter). Recently, PC-based analyzers have appeared on the market. But they are also quite expensive - close to $ 4000 AirSleuth is an affordable 2.4-GHz spectrum analyzer shows available Nuts About Nets, LLC, that RF data in aVariety of diagnostic views that help to reveal the presence of interfering devices and then choose the best channel for your wireless network.
Examples
Click here to see included 5 Examples of measurements with the AirSleuth 2.4-GHz spectrum analyzer. In each picture there are 3 items to take note of:
a. The maximum value on the y-axis
b. The horizontal white lines indicate that the limits of the 11 overlapping channels 802.11
c. TheLocation (ie frequency) and height (relative signal) of the large HF Summit
Figure 1 In this figure, the horizontal white line shows the limits of 11, 22 MHz channels in the 2.4 GHz band. Note how adjacent channels overlap.
Figure 2 The airspace is relatively quiet and there are no wireless devices transmit in the 2.4 GHz band. Note the maximum value on the y-axis is '3 .0 'relative signal units --this is small. The reason you see peaks (and starting) is not quite flat, the display employs automatic scaling so that (the highest peak regardless of how small it really is) filling the screen. We know what looks background noise, since the maximum value on the Y-axis <10.0.
Figure 3 is running a microwave oven. Here you can see that it radiates RF energy over the entire 2.4-GHz band.
Figure 4 is a 2.4 GHz cordless phoneturned on. Note the height of the peak near channel 1 around "140" units and the peak near the channel 11 is around '110 'units. These are strong enough to knock out wireless networks are configured to use either channel 1 or channel 11. Moreover, because of the way that channels overlap the first peak would probably also interfere with a wireless network with channel 2, and the second summit would also interfere with wirelessNetworks with 9 or 10 channels.
Figure 5 shows the course of the activity from a wireless network (configured to channel 6) to use, since it operates a large stream of data transmitted.
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