The 2.4 GHz band is a license-free radio range shared by Wi-Fi, Bluetooth, Zigbee and many wireless cameras and sensors. It carries further and passes through walls better than 5 GHz, but the available spectrum is narrow and crowded, so interference is common in offices, warehouses and apartment buildings.
Wireless security devices rarely get spectrum to themselves. They compete with access points, cordless phones, microwave ovens and the networks of every neighboring building, and that crowding shows up as dropped video and missed sensor events.
Channels overlap by design
North America allows 11 channels, and only 1, 6 and 11 avoid overlapping each other. Two devices on different channel numbers still interfere when their channels overlap in frequency.
Why cameras and sensors use it
The longer wavelength gives better range and wall penetration, which suits doorbells, gateways and sensors at the edge of coverage. A site survey and a fixed channel plan matter more than raw signal strength.
Related:Commercial security camera systemsGlossary: Access control system