Figure 2a—Even at a distance of 30', the sensitive receiver can detect a signal leaking from a microwave. Such signals can disrupt Wi-Fi communications in the area. b—The spectrum of a 802.11b access point operates on channel 9. The 22-MHz transmission centered at 2,452 MHz is visible, as are some side lobes. c—Take a look at the spectrum of a Bluetooth-enabled PDA searching for nearby devices (a so-called “inquiry sequence”). During an inquiry, a subset of the 79 possible Bluetooth channels are used. The channels are visible as peaks in the spectrum.