Performing Spectrum Analysis
Get the details about how Chanalyzer works, learn how to interpret displayed data, and review the best practices for using Chanalyzer when you're on-site.
How Chanalyzer Works
Chanalyzer combines data from Wi-Spy and your computer's wireless network adapter into a series of interactive graphs and charts. While the Wi-Spy will show you all RF activity, it is not a Wi-Fi adapter. It can "hear" transmissions from wireless devices but it does not decipher which devices are transmitting like a network adapter would. This is similar to hearing a conversation in another language -- you know people are talking, but you don't know what they're saying. Chanalyzer is also capable of displaying data from a Cisco CleanAir-enabled access point. Wi-Spy doesn't distinguish between Wi-Fi and non-Wi-Fi sources, so Chanalyzer utilizes your Wi-Fi adapter to display information about nearby access points including their channel, RSSI, and security type. If your computer is connected to a Wi-Fi network, your Wi-Spy may display all of your Wi-Fi adapter's transmissions. If you are in an extremely saturated environment, it might be beneficial to turn off your Wi-Fi adapter completely.
The moment you connect your Wi-Spy to Chanalyzer, Chanalyzer begins to record, just like your television’s DVR. Using Waterfall Navigation, you can "rewind" your recording to the precise time interference occurred while current data is still being captured.The time frame selected in the waterfall controls the range of the data displayed in the Details and Overview Panes
Chanalyzer’s Overview Pane graphically displays the data that Wi-Spy is currently collecting. In the toolbar above the pane, you will find different display options for Wi-Fi network overlays and interferers. The Density View displays the data in a range of colours from blue for infrequent transmissions, to red for constant utilization (and high risk of interference).
The Overview Pane also features a Waterfall View representing the amplitude history of your selected time frame.
The Details Pane is located below the Overview Pane. Here you will find a number of tabs with more in-depth information about your surrounding Wi-Fi networks and the spectrum congestion levels calculated for each Wi-Fi channel.
Of particular interest in the Details Pane is the Networks Table, which displays a list of all of the Wi-Fi access points within range of your current location. This table can be filtered to display only the network(s) belonging to you or your client. Keep in mind that Wi-Spy is unable to read Wi-Fi at the packet layer, so your computer needs a dedicated wireless network adapter in order to populate this table. If running Chanalyzer in a VM, a USB Wi-Fi adapter must be used to capture network data.
Learn more about the other tabs in the Chanalyzer User Guide.
Here are some suggestions that will help you get the most out of Chanalyzer:
Save a .wsx File
After you've completed the survey of your area, you can save your recording in Chanalyzer's file format, .wsx. You should also consider documenting your findings with a spectrum report.