The process of digitalization is unstoppable, even taking hold in places of historical significance. For example, where buildings under monument protection are being converted into modern offices, or in centuries-old buildings such as museums or theatres which, of course, have to keep pace with the digital age.
This is the collision of two worlds that need to come together. One world is historical, it needs to be preserved and changed to a minimum and only very carefully: The other is digitalization, which has one principal lifeline: high-performance (wireless) networks.
Do not touch the walls!
Modern networks depend on mobility and flexibility. This is why Wi-Fi is so often the preferred choice when it comes to seamless networking in listed buildings. But it’s a tough task! Ultimately, many historical buildings are subject to strict preservation regulations.
The crux of creating powerful networks in heritage buildings centres on the question of how to integrate modern components as discreetly as possible without making significant changes to the buildings themselves.
Our Field Application Engineers, who accompany our customers on projects, have reported some quite surprising approaches. On one project, the Wi-Fi antennas were given a special coating so as to fit-in with the wood-panelled surroundings. On another project, the network components—including the cables—were concealed inside the furniture, so that the installation remained completely invisible from the outside. Creativity is in demand here.
Bricks, steel and concrete
Another decisive factor that determines which solution leads to the goal are the characteristics of the wireless LAN itself. Technically, the strength of a wireless network depends on two factors: the distance to the base station, and the obstacles in between. Through the air, the range of a Wi-Fi cell can be up to hundred meters, whereas solid materials such as stonebrick, or concrete lead to considerable signal attenuation, and metal actually reflects the waves as well. Wood or uncoated glass barely obstruct the radio signals at all and absorb the signal only slightly. With glass, things are more critical if the glass is laminated with a metal wire mesh or has been coated with a layer of aluminium as both tremendously reduce Wi-Fi signal transmission. What’s more, historical buildings like castles or fortresses can have meter-thick walls, and a wide variety of materials may be encased in the walls or ceilings. A certain amount of ingenuity is needed here.
Signal strength is also affected by the frequency band used by the Wi-Fi. The shorter wavelengths of the 5GHz bands mean that the range is less than that of the 2.4GHz band. On the other hand, there are far fewer sources of interference in the 5GHz band which, under optimal conditions, allows higher transfer rates. The use of dual-radio access points, i.e. devices with two radio modules, offers the advantage that both frequency bands can be leveraged to best effect.
Where signals are obstructed by thick walls or metal, the only option is often to take a detour around several corners or to signal through “thinner” materials such as wood or glass as in available doors or windows for example. Also, the angle of incidence of the signal on an obstacle can lead to signal attenuation or reflection. The skilful placing of special antennas (directional antennas, omni-directional antennas) can minimize reflections and improve the signal.
If the goal is to overcome large distances, for example between two widely spaced wings on a large property, point-to-point (P2P) connections are the first choice. Here, wireless LAN access points form a wireless point-to-point link, where one access point transmits to a second access point via a line-of-sight transmission path. Where the distance is too far, or where the buildings have passages that are too twisted, the signal can be passed along a number of additional access points acting as a relay stations.
If this does not help either, the only solution is to combine different technologies. For example, technicians combine Ethernet cable with Powerline adapters to transmit the network signal via the mains power circuit. This combination of wired and wireless connections is often the only way to overcome major obstacles such as extremely thick walls or ceilings, or to cover longer distances in labyrinthine buildings. In very distant locations, it may even be necessary to go via the cellular network, and use combined 4G/Wi-Fi routers with LTE as access to the WAN.
Beaming from the outside
In extreme cases, the network infrastructure may even need to be moved outside. Robust outdoor access points are mounted on poles and the Wi-Fi signal is beamed into the building through the windows. This means that the technological components remain invisible from the inside, and there is no need to drill holes for cables or fixtures.
As you can see—or maybe not see—there are no limits on the imagination in implementing a comprehensive network within historical buildings. To be sure of signal coverage in any nook or cranny in labyrinthine buildings with meter-thick walls, you can rely on the WLAN specialists to come up with the right idea.