New and used wireless camera systems and devices, from surveillance and nanny cams to sunglasses and other fun items.
Wireless camera systems operate in much the same way as any other wireless device; in this case, a transmitter in the camera and a receiver in the base, both operating on one of a couple of transmission frequencies which include 900MHz and 2.4GHz.
Just like using the radio to tune into a frequency that is carrying a signal, the base is tuned into the frequency that the wireless camera transmits on. The wireless camera simply transmits the video data through the frequency to the receiver located in the base and then moved on to a video recorder, monitor, or whatever wireless application is being used.
Since the cameras are wireless, they also have no cables connected to deliver power, and thus requires power from batteries. The limitation in the size of a wireless camera is directly related to how small a manufacturer can make not only the camera, but the transmitter and power source.
Some wireless cameras can be plugged into a power source leaving only the camera signal wireless.