Probably because I'm microwaving my dinner? I dont know whether most folks are aware of this or not but the average Microwave oven seriously leaks EM radiation in the 2.4Ghz frequency range and if you have a wireless LAN at home this might be a problem. It is probably also worth seeing the effect if you are concerned about radiation from cell phone masts because this stuff is a hell of a lot stronger than cell phones (range of kilowatts of radiation vs range of watts of radiation).
Anyway some snaps from tonight courtesy of my $100 WiSpy 2.4Ghz EM radiation detector. Great geek toy, every home should have one.
This is the signal with me copying down a very large file over WiFi Channel 6 (2.436 Ghz +-5 Mhz) Notice the very nice clean signal centered on channel 6.
Then I turned on the Microwave. OK so the signal doesn't quite fall apart at the seams but it is quite shocking to see that the most conservative interpretation would say that the signal at 2.455 - 2.466 Ghz is completely annihilated by my Microwave and by and large there is major interference at all frequencies at or above 2.436 Ghz (Channel 6).