Wireless surveillance cameras have built-in transmitters that send video over the air instead of through a wire. Some wireless surveillance cameras are still plugged into a power source, but are called wireless because of how they transmit videos. Other cameras are battery-powered and are truly wireless.
Wireless surveillance cameras transmit either an analog or digital signal. Analog cameras send out a constant string of data that can be picked up by any receiver in its frequency range, but that also makes interference more likely. Digital cameras modulate their signal and cycle through frequencies to avoid interference and make transmissions more secure.
Most wireless cameras are available in either 2.4 or 5.8 gigahertz. The 2.4 gigahertz models have a range of 700 feet and can carry a maximum of four transmissions, while the 5.8 gigahertz models have a range of 2000 feet and can carry a maximum of eight transmissions.
Some wireless surveillance cameras use Wi-Fi and allow multiple devices to be networked together through a wireless router. Routers usually only have a range of no more than 300 feet, but Wi-Fi cameras allow remote access to a video feed from outside the network. Wireless cellular cameras are also available, and they contain a cellular transmitter that connects to a cellular network.