If you distrust five of your senses and the sixth isn't returning your calls, it may be that your environment has become sodden with microwaves. Too airy and hectic to be detected using old-school sensory apparatus, the microwaves that transport your digital diet through the walls and hallways of your neighbor's house are the same energy puffs your neighbor uses to meet his own daily requirements, which is just a fancy way of saying that the hood's available bandwidth is inversely proportional to its appetite. This is why your wireless router is such a reliable source of madness.
While many have approached this problem from the two-pronged vantage point afforded by inSSIDer and Nmap, diplomacy shouldn't be entirely ruled out. If your neighbor is a reasonable man, he will immediately understand how delusional he is to believe that there are eleven Wi-Fi channels in the 2.4 GHz band; if your neighbor is a reasonable woman, she will immediately see that there is room for only three. On the other hand, if both stream terabytes at 300 Mbps and laugh when you demand they use the 5 GHz band instead, it may be time to go home and rethink your stubborn refusal to give up your Tomatoed 54GL.
History bites its own tail, and technology never does. Radio silence will come again, but how many senses will you have by then?