There are few important things which must be kept in mind while purchasing a wireless spy camera. It is the characteristic which is used by the camera to broadcast the video signal. Most applies ranges are 434 MHz, 900 MHz, 1.2 Hz, 2.4 Hz and 5.8Hz. Another important is the range of transmission. It measures the distance between the camera and the receiver. It is due to the fact that there can be obstacles between the spy camera and the receiver.