CCTV camera technology is advanced and sophisticated, requiring specialist knowledge by a CCTV installer to install and set up correctly. There is a vast array of options, together with terminology that you may not have heard of before. So we decided to create this guide to help you understand CCTV cameras better when considering home or business CCTV installation. If you need any help while reading this guide, please call us on 020 3282 0453

As well as installing CCTV systems, Techcube also supply equipment, including CCTV cameras, DVRs (Digital Video Recorders), NVRs (Network Video Recorders), and also tools to carry out CCTV installation. Please contact us here.

When buying a camera system, many factors must be considered, for example how the system will be used, technical CCTV camera specifications and constraints of the environment into which the

CCD Chip Size & Chip Sets

The main function of a CCTV camera is to capture light and convert it into a video signal. At the core of a CCTV camera is a CCD sensor (Charge Coupled Device). This converts light into an electrical signal. Signal processing converts the electrical signal to a video signal that can be displayed on screen or recorded.

The CCD is made up of optical detector integrated circuits that use semiconductors. The camera lens focuses light on the CCD image sensor. Photo diodes sense the image areas of light and dark and this results in an electrical charge in proportion to the level of light. A brighter area will result in a higher charge. The photo diodes form a matrix of rows and columns and are called picture cells or Pixels. The charge on the diodes are then processed.

CCDs have a variety of surface sizes, typically 1/2 inch, 1/3 inch, 1/4 inch and 1/8 inch. To summarise, these are not the actual sizes of the sensors, but based on their video camera tube equivalent, as historically, image sensors were used to replace video camera tubes, so a sensor with a 1/4 inch digital sensor is more accurately described as a ‘1/4 inch video camera tube equivalent’.
Analogue Versus Digital
Analogue

In an analogue camera system, the camera captures an analogue signal and this is transferred via a coax cable to the DVR (Digital Video Recorder). The DVR converts the analogue signal to a digital one, compresses it and this is stored on a hard drive within the DVR. The footage can be viewed on monitors attached to the DVR or the signal can be sent across a network to be viewed on a computer screen. The DVR can be set up to transmit over the internet and when this is done with an analogue system, all of the cameras’ signals are sent as one stream using one IP address and this makes it very efficient.

Digital IP Network Cameras
With digital IP (Internet Protocol) cameras, each camera captures an analogue signal, but this is converted to a digital signal within the camera itself. Digital processing may also occur within the camera. The digital signal is then sent via a LAN (Local Area Network). The cables used here are Ethernet, e.g. Cat5e.
Instead of the analogue system’s DVR, for IP cameras, the video from each camera is compressed and recorded onto an NVR (Network Video Recorder). The key difference is that the signal is digital and a much higher resolution (see further down in this guide) than analogue. The NVR streams the video from all cameras and broadcasts over LAN and over the internet for remote viewing.

DSP – Digital Signal Processing
Digital signal processing cameras utilise a DSP chip to convert analogue video signals to digital. The analogue signal is generated by a CCD chip (charge coupled device – see above) and then the DSP chip converts to digital. DSP camera benefits include increased brightness, greater stability of image, a sharper image and better power efficiency. There is also reduced sensitivity to noise.

Camera Cables and Connections
An effective CCTV camera system requires correct and high quality cabling and connectors to connect the components of the system together.

Siamese Coaxial Cables

This cable is two cables joined together to supply power and the video signal. This cable is otherwise known as RG59. The video element of the Siamese cable allows transmission of video signal from the camera to the DVR. The power cable supplies power to the camera from the power box. The power cable uses a BNC connection. Siamese cable is compatible with analogue camera systems or High Definition (HD) systems that utilises coax, e.g. HD-CVI or HD-TVI cameras.
It’s important to use the right gauge cable, i.e. the thickness of the cable. Gauge is measured in AWG (American Wire Gauge) and the smaller the gauge the thicker the cable. Thicker cables allow it to use power more effectively and cable gauge should be chosen based on the application.

Cat5e Ethernet Cables

Cat5e cable can be used for analogue or IP cameras and allows video transmission of up to 3000 feet.
This cable uses the RJ45 connector. This is a popular cable for CCTV systems and is vital to IP camera systems. Cat5e is ideal for analogue systems but needs to use a video balun (converter) to allow traditional coax to be replaced.

Cat5 cables are poor quality and not to be used with CCTV systems, Cat5e is the better cable for these applications.
How you power your cameras is something else to keep in mind with Cat5e. There is a system called PoE, Power over Ethernet, which we will discuss now.

PoE – Power over Ethernet
PoE (Power over Ethernet) is a technology that allows cameras to be powered from a single Cat5e network cable. Normally a camera requires 2 cables, one for video signal and one for electrical power. If a camera is enabled with PoE then only one cable is required that supplies power and also handles the video signal.

Benefits of PoE
Saves time and cost – savings can be made by not having to install electrical cabling. Network cables do not require a qualified electrician for installation.

Location of cameras – as cameras do not require a power outlet, they can be located anywhere and can be relocated easily if required.

Safety – PoE is an intelligent system and protects equipment from incorrect installation, power overload, or under powering.

Reliability – power originates from one source rather than disparate wall sockets, so improves reliability of power. PoE can be backed up with another power supply in case of failure.

Scalability – distribution of the network is easier with PoE.

Wired and Wireless
Cameras can be wired or wireless.

Wired cameras use cables with PoE (Power over Ethernet). PoE means that you only have one cable attached to each camera, making installation easier.

The signal from wired cameras is not affected by loss of internet or interference, so the signal is more reliable. Wireless cameras are affected by loss of Wifi or a weak Wifi signal caused by walls and weather for example.

Wireless cameras have the major benefit that no holes need to be drilled into walls and if you remove the wireless camera installation then the property is unaffected and left as it was prior to the installation.

Wired cameras are usually used in commercial and business settings whilst wireless is more popular for residential us