We were having an issue with bandwidth availability and packet loss in that section of the building, particularly in that classroom. It was likely an overload issue and has since been resolved (upgraded from single radio to dual radio with N), but it still appears there is some interference in channel 11 on the 2.4 ghz band (hence the red line). I'd like to get it cleaned up, if possible, but I want to make sure that it actually is interference.
In the originally attached image, there is a pretty solid red line in the center of channel 11 that does not appear in other channels, so I was wondering if it was normal to appear that way or was it something worth investigating as possible interference. That's why I wanted to see a healthy spectrogram, for comparison.