Notes on operating range of Radioeye® wireless cameras

Analogue and digital transmission

In all classic CCTV systems each camera is connected to the monitor or video-recorder by cables. If the site does not permit running the cables the only solution is making a wireless bridge installing a transmitter closed to the camera and a receiver near the monitor/DVR.
Todays there are 2 kinds of Audio/Video transmitters on the market: analogue and digital.  
Analogue video transmitters have been very popular for several years. They transform the analogue video signal of the camera in a RF modulation.
Digital video transmitters are the state-of-the-art technology in video transmission. In this transmitters the analogue video signal is first converted in a digital stream before being transmitted. The receiver re-decodes the digital stream in an analogue video so that any TV set, DVR or monitor can be connected. Compared with analogue transmitters, these digital equipment provide much better RF immunity and 100% noise-free video.

Difference between digital transmission of analogue video and Wi-Fi

First of all it must be clear that digital transmitters for analogue video, like RE-DTX, have nothing to do with Wi-Fi.
Wi-Fi is used by IP cameras that generate a digital video to be played and managed by computers. On the contrary, in the digital transmitters of analogue video the digital stream exists only between transmitter and receiver, while the input from the camera and the output to the monitor are pure analogue composite video that can be connected to any video equipment like TV sets, video-recorders, video cameras etc.

Advantages of digital transmission

The recent development of digital transmission dramatically changed the market of wireless CCTV systems as well as it modified the world of broadcasting TV.  
The great advantage of digital RF transmission is that only 1-0 data are transferred instead of "From..To" values as in the analogue transmitters. For this reason the digital transmitters provide a clear noise-free video or nothing at all in case their operating range is exceeded. The "almost clear, so and so ..." area, typical of analogue transmission is not existing.
Besides this fundamental difference, the digital video is managed by a microprocessor, so several important features can be added for example in  order to improve RF interference immunity or to avoid unauthorized reception of the transmission.

Line of sight range and indoor range

Line of sight range
This is the maximum distance between a camera and receiver when there are no obstacles between the two, ensuring that the radio waves can travel freely through the air. The line-of-sight range can be measured fairly accurately using the appropriate methods. It should however be considered an approximate figure, as it can vary according to environmental conditions and external interference.
Indoor range
This is the maximum distance between a camera and receiver when there are various kinds of obstacles in between, such as walls or furnishings. The indoor range obviously depends on the number and type of obstacles present, as well as reflections off walls, and is therefore difficult to measure accurately.

Transmission in line of sight

The range of all DSE audio/video transmitter is always guaranteed in a line-of-sight condition (no obstacles between the antennas).
When designing your system, you should attempt to ensure maximum line of sight, to guarantee the best transmission range. However obstacles do exist and it is necessary to find a way round them. Every obstacle inevitably means a certain loss of signal, which is why it is important to ensure there are not too many, which would lead to a complete loss of signal.
Below are a few indications on how to deal with obstacles.

Obstacles to wireless transmission

What type of obstacles can influence transmission?
TThe obstacles which can influence wireless transmission from a Radioeye® camera are those located on the imaginary line between the receiver antenna and the camera antenna. Any other obstacle in the vicinity, or above or below, will have little influence. This is why the position of the camera is very important, as moving it by one meter can sometimes be enough to get around obstacles.
Metallic obstacles
Metal is the only substance commonly present in everyday applications which is capable of completely screening a wireless signal. If you were to shut a camera inside a sealed metal container, no signal at all would get through, even with the receiver right alongside. Fortunately it is rare to come across obstacles entirely composed of metal, but it is important to look out for large metal gates or metal shelves. It is also important to remember not to install the camera inside a metallic “cage” such as a lorry or closed cab, unless you are able to position the antenna on the outside, as described below.
Non-metallic obstacles
Non-metallic obstacles do not entirely screen wireless signals, meaning that the signal from a RadioEye camera will pass through. Each obstacle encountered does however introduce a certain level of signal attenuation. Thicker, denser obstacles, such as thick cement walls or roofing slabs weaken the signal more than less dense, thinner materials like wood, plastic etc.
The importance of the location of obstacles
There is a general rule here: the nearer the obstacles are to the transmitter (the camera), the weaker the signal will be. It is therefore a good idea to avoid positioning a camera immediately behind a wall (with respect to the receiver), because the signal would be weakened at the outset. The camera should be positioned in the most open location possible, pointing towards the receiver and ensuring there are no large obstacles near the transmitter, where the radio wave is narrower and it is more difficult to get round obstacles.
 

Maximum operating distance between camera and receiver

For each wireless equipment DSE declares an open air, line-of-sight, maximum operating range which can be achieved without obstacles and in optimal environmental condition. This figure can be measured quite accurately,  but can anyway vary considerably according to the environment. In the event the presence of obstacles cannot be avoided please consider the following range reduction:

Increasing range with directional antennas

RadioEye® cameras and transmitters come with omnidirectional antennas which transmit in all directions. However these can be replaced with a directional antenna which transmits in one precise direction. Directional antennas are usually connected to cameras and pointed in the direction of the receiver. Usually they are installed outdoor and connected to the camera by means of a cable (RE-CA4/5/6).
Using a directional antenna increase considerably the open air range, even over 50%.
The indoor range, is also improved but the benefit is reduced according to the number of obstacles.