IMMI Screenshots at Atlanta International Airport

The following screenshots were taken at Hartsfield-Jackson Atlanta International Airport. We were looking for an environment with lots of WiFi traffic and happened to be passing through. This airport is no different than others or, for that matter, other high traffic areas — such as corporations, business parks, hospitals, universities, etc. The screenshots were taken using WifiEagle and highlight the ability of IMMI channel analysis technology to compute the best WiFi channel in a “hostile” environment — that is, one in which there is a lot of RF activity. This would be almost impossible using an RF spectrum analyzer since the resultant spectrum traces would be very complicated with lots of peaks and valleys. This is an example why a tool that uses IMMI is a better choice when the goal is to determine the best WiFi channel — i.e. the one least affected by RF interference and which offers the greatest available bandwidth.

* NOTE: For enlarged views, click on an image.

IMMI Channel Analysis

	The grid in the upper-left corner lists all channels, along with their relative available throughput.  The larger the percentage means more bandwidth is available (since there is less RF interference affecting that channel).  According to the grid, channels 2,3 are the best, and channel 5 is the worst.   The heatmap in the upper-right corner shows the same result — red implies more available bandwidth (i.e. less RF interference) and blue means less (i.e. more RF interference).  The statistics view shows channels 2,3 with the greatest available bandwidth and channel 5 with the worst.
	Same result as above.  The spectrogram view shows the relative available bandwidth for each WiFi channel as a function of time.
	Same result as above.  The timecourse view shows the relative available bandwidth for each WiFi channel as a function of time.
	Same result as above.  Here the main screen shows the grid and all diagnostic charts — heatmap view, timecourse, differential, spectrogram and statistics.

802.11 Network Discovery

The following screenshots were captured at the same time as those above using WifiEagle’s built-in network discovery module. They serve to illustrate the difference between channel analysis, which measures the effect of RF interference on each channel, versus network discovery, which listens for beacon signals transmitted by each AP.

	The upper grid lists all the APs at the Atlanta airport.  The channel usage chart groups the APs according to the WiFi channel they are currently using and their beacon’s signal strength.  From this chart it is apparent that channel 1 is the most popular channel.  Furthermore, there are no APs using channels 2, 3, 4, 7, 8 or 10.  From this data there is no way for us to know that 2,3 are the best channels and 5 is the worst.  That’s because network discovery simply detects beacons and does not measure the level of RF interference that affects each channel.
	The heatmap chart agains shows that channel 1 is the most popular WiFi channel.  That is, the collective beacon strength of all APs using channel 1 is greater than other channels.
	The spectrogram view shows channel usage as a function time.  The green bars represent channel 1.