An instrument is disclosed that is capable of detecting and graphically displaying channel usage and the number of access points operating on each channel of interest. By using a module that counts the number of elapsed clock cycles, the total cumulative duration of detected frames, and the number of channel in-use cycles, the instrument can determine the percentage of time a channel is in use, the percentage of time of IEEE 802.11 usage on a channel, and the percentage of time of non-IEEE 802.11 usage on a channel. Further, channels are scanned for access point activity using a scanning algorithm that interleaves scanning channels at a first duration longer than the beacon interval and scanning channels at a second shorter duration.