Interference overview
New building structures have the capability to degrade the integrity of television signals as they travel through free space from transmitter to a receiving aerial or satellite dish. These obstructions can impede the television signal strength and/or prevent its reception altogether.
In urbanised environments, the impact of a new building development upon television signals can often go unnoticed. This is because the addition of similarly sized buildings in the area – e.g. additional homes within a housing estate – will be unlikely to significantly affect the baseline conditions. However, when a new structure is built which is larger than those in the surrounding environment, television interference is more likely to occur.
Building developments – terrestrial television interference
There are numerous reports throughout the UK and internationally of terrestrial television reception being affected by large building developments. In many cases this has occurred because a building has been located a particularly sensitive location between the transmitter and receiver. This scenario occurred in Blackpool for the Talbot Gateway building development [1].
Figure 1 below shows a simplified interpretation of how a building development could interfere with terrestrial television signals. A variety of factors including diffraction and reflection effects, as well as the surrounding terrain and built environment, will affect whether significant interference is experienced.
Figure 1: Terrestrial television signal obstruction
Building developments – satellite television interference
In a small number of cases satellite television signal can be affected by the presence of a building development. This type of television receiving equipment is orientated towards a geostationary satellite at the equator which circles at the same rate as the earth’s rotation. For this reason, satellite and receiving dish are always in line with one another. The receiving dish is therefore tilted upwards at an angle relative to the location of the satellite. The degree of tilt required depends on the latitude of the receiving equipment. The further north or south of the equator you go, the smaller the angle above the horizontal required.
Figure 2 below shows a simple illustration of how a building development could obstruct a satellite TV signal.
Figure 2 Satellite television signal obstruction
Satellite television interference case study: Abu Dhabi
Residents living near to the Sharjah Mega Mall in Abu Dhabi of the United Arab Emirates (UAE), complained as their satellite signal television receiving equipment no longer worked.
The residents living in the shadow zones of new building developments and construction equipment [2] encountered a complete loss of satellite television signal. After, it were discovered that the new developments were now completely blocking the line of sight between the receiving dish and transmitting satellite.
It appears that planning laws in the UAE do not protect the provision of television coverage however Abu Dhabi’s Urban Planning Council are now preserving its flat 20-storey to 25-storey skyline whilst restricting taller buildings in certain areas. The aim is to create a more uniform skyline, however it will also help reduce the likelihood of satellite television interference occurring.
Why should you investigate the effects of your building development on television signals?
Put simply, it can be an unknown and expensive problem to fix. There can be a requirement to mitigate any significant detrimental impact upon the provision of television signals.
Encountering unknown additional costs post-construction can be problematic. Mitigation is often required quickly and therefore it is important to consider the effect that a new building development on the provision of television signals.
Can We Help You?
We can offer detailed Desk Based Television Impact Assessments, Baseline Television Reception Surveys and Post-Construction Television Reception Surveys.
Please get in touch if you would like further information or would like to discuss a project.
[1] “Lost transmission blamed on major building scheme“, The Blackpool Gazette (last accessed October 2014)
[2] “High-rise towers blocking satellite TV signals“, The National UAE- (last accessed October 2014)
