Wi Spy USB Spectrum analyzers

My home requires six WiFi access points (AP)for full coverage and "four bar" indication virtually everywhere. To minimize interference among them, I allocate a different channel to each AP, but since there are only three channels available for high speed WiFi in the 2.4 GHz band, some APs would have to use the same channel. WiSpy is the ideal tool to observe, using a laptop PC, the activity at each location, including my own APs and neighbors equipment. It was easy to install and set and with all display options I could develop a feeling of the best channel for each AP, including interference from non WiFi equipment. Now I use it occasionally to troubleshoot coverage issues. For less than $100 it is a great spectrum analyzer.