Installing cables from CCTV cameras to a recorder can be a time consuming task. It also requires a good knowledge of CCTV installation methods. Poorly cabled CCTV installations often result in image quality problems and generally look untidy. Wireless CCTV cameras are a very attractive proposition to the amateur or DIY installer. Less cabling makes installations quicker, neater and on the surface it seems like the best option.
Wireless CCTV comes in two distinct flavours and understanding the differences as well as the pros and cons for each type is important before deciding to go wireless.
Analog wireless transmission.
When an analog signal is transmitted using wireless it is a continuous signal which varies with the level of colour and detail in the picture. The shape of this signal determines the final picture so it is vital that the signal is unchanged when it reaches its destination. A wide range of electrical devices cause interference which can lead to the signal changing shape. The result of changes to the signal caused by interference is distortion or complete loss of the final image.
Digital wireless transmission.
Digital signals are transmitted as a simple on and off commands. These are transmitted in blocks which allows other data to be sent at the same time. The shape of the signal is less important as the receiver only needs to determine whether each part is on or off. Interference causing small changes in the signal will not affect the image as long as the receiver can differentiate between the on and off parts of the signal.
Analog wireless transmits the video directly. Any receiver capable of receiving the correct frequency can receive this and display the resulting image. This means the signal is insecure and can even be received by nearby devices inadvertently.
Digital wireless uses the 802.11x communication standard also know as wi-fi. This standard has various encryption methods built in making it very easy to add security to the transmission. The data can be encrypted before transmission and then decrypted by a receiver with the correct security key. Any receiver without a matching security key will be unable to decrypt the signal and view an image.
Analog and hybrid digital cameras output images using analog signals. This makes wireless transmission of these types of cameras unreliable and insecure. Low cost wireless CCTV cameras use analog transmitters and are generally a poor choice as a security device.
Each analog wireless device requires a unique frequency. As a result the number of units that can be installed within the same area is very low and multiple devices often interfere with each other.
Due to the limitations of analog wireless signals, connecting CCTV cameras with a cable has previously been the method favoured by professional CCTV installers.
Wireless IP CCTV systems
Modern advances in CCTV technology now allow cameras known as IP CCTV cameras to transmit images as data. Data can be transmitted digitally meaning that the signals are less prone to interference, are more secure and can be transmitted over greater distances.
Multiple wireless IP cameras can use the same frequency as the data identifies the camera. This allows sites to have large numbers of wireless cameras without risk of interference.
IP CCTV is however more advanced technology making equipment costs higher and configuration more complex. Inexperienced users should seek professional advice when considering a wireless IP CCTV installation.
Wireless technology would rarely be a first choice for connecting CCTV cameras. Cables are secure, reliable and inexpensive over short distances. There are times however when it is impractical to use a cable to link devices. If this is the case a professionally installed digital wireless CCTV camera is the best solution. Digital wireless cameras can even be added to analog systems saving the cost of a complete upgrade. If your application requires use of wireless technology our advice is to look for a digital IP based system.