Specialist Systems
Infra-red lighting
Camera's need a sufficient amount of light to capture images adequately. This light can be
produced using sources of white light, eg Metal halide or sodium discharge lamps. The running
costs of systems incorporating this form of lighting can be quite prohibitive. Additionally, certain
brazen criminal elements prefer that a location is brightly lit as it allows them to carry out their
criminal activities easier.
Alternatively, Infra-red lighting can be employed.
There exists 2 forms of infra-red lighting. One is in the 940nm wavelength which is not visible to the human eye which is of particular use in covert systems, ie. CCTV systems which aim to capture images of individuals behaving in a suspicious manner without them being aware that their images are being recorded. An alternative system employing light occupying the 850nm wavelength. These lamps give off a red glow and can be used in situations where it is felt that the deterrent effect is more desirable.
Wireless systems
For the majority of CCTV installations, hard-wired cable systems are preferred. This ensures the pictures returned to the recording unit are of the highest possible quality. However there can be instances where a fully cabled systems would not be appropriate. In the case of a car show-room for example which might span two sides of a public highway. In this case it would not be practical to run a cable from one or more camera's on the opposite side of the road to where the recording unit was being kept. In this case it would be necessary to incorporate a wireless method of transmitting images. Although the image quality is not significantly reduced other factors can affect the image quality such as weather conditions. A drop in atmospheric pressure can lead to significant deterioration in picture quality. Additionally there are brief occasions when the signal can momentarily drop out altogether.