Software spectrum analyzer on a regular WiFi card

    A group of researchers from the University of Wisconsin-Madison developed AirShark software, which, with a WiFi card, detects the presence of signal interference sources such as microwave ovens, Bluetooth and ZigBee devices, cordless phones, wireless video cameras, Xbox / Wii consoles. Accuracy ranges from 91.23% to 100%, depending on the received signal strength (RSSI). The graph shows the analysis of the radio spectrum for 24 hours in a room such as a student dormitory, indicating the types of devices and signal strength

    It is assumed that the detection of interference will automatically adjust the WiFi band to ensure maximum data transfer quality. For example, if Airshark is standing on a WiFi router and a cordless telephone turns on nearby, causing interference in the frequency range of less than 1 MHz, the router will automatically narrow the data transfer band of the client from the usual 20 MHz to 10 MHz to avoid interference.

    A unique feature of AirShark is that it does not require any additional equipment, expensive spectrum analyzers. This is a purely software solution that can be installed on any computer with WiFi, it works with the map API.

    As tests have shown, the level of false positives is 0.39% for an environment with four or more simultaneously interfering devices, with different received signal strengths from -80 dBm to -30 dBm. This indicator drops to 0.068% for signals more powerful than -80 dBm. In general, the quality of the program is no worse than a conventional spectrum analyzer.

    Interestingly, if you put AirShark on several routers close to each other, they can even determine the physical location of the interference source by triangulating the signal.

    The research results are published in a scientific article by Airshark: Detecting Non-WiFi RF Devices using Commodity WiFi Hardware (PDF).

    via Network World

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