I took the advice of Bernie and downloaded iStumbler, a wireless sniffer for the Mac OS X.
As you can see from the screen shot, the app has a much more sensitive “nose” being able to sniff hot spots way further than the built in wireless detector of the MacBook. Well, no surprise really. This is precisely the reason why iStumbler and other wireless sniffers have their demand on the virtual shelves.
Best of all, it is free!