Electromagnetic Interference Problems

Electromagnetic Interference Problems in Television Sets

Electromagnetic Interference Problems in Television Sets

The electromagnetic interference in TV sets is a common problem that affects signal quality. It can be caused by both internal sources and external factors. To solve it, it is necessary to take measures such as using appropriate filters, ensuring quality connections and cables, avoiding signal overload and eliminating sources of interference. It is also important to pay attention to interference problems in digital terrestrial television (DTT) reception.

What is electromagnetic interference in televisions?

Electromagnetic interference in TV sets is a common problem that can affect the quality of the TV signal. It occurs when electromagnetic waves from different sources overlap and cause disturbances in the signal, resulting in picture and sound problems.

These interferences can have a variety of causes, both internal and external. In the case of internal sources, they can be caused by items inside the home such as poor quality LED lighting, wireless routers near televisions, electric motors in household appliances or boiler thermostats with faulty electronics.

On the other hand, external sources of interference can be caused by vehicles with poorly insulated spark plugs, buildings under construction that generate echoes, poorly filtered antennas, adjacent channels that partially overlap, trees that obstruct the signal, among others. Factors such as fading in coastal areas or electrical fences without proper grounding can also play a role.

It is important to bear in mind that these interferences can affect both analogue and digital reception, being particularly relevant for digital terrestrial television (DTT) signal reception.

In the next section, the sources of internal and external interference in TV sets will be discussed in more detail.

Electromagnetic Interference on TV sets

Sources of internal and external interference in televisions

The electromagnetic interference in televisions can have different sources, both internal and external. It is essential to identify and understand these sources so that appropriate measures can be taken to minimise their effect on signal quality. In the following, internal and external sources of interference in TV sets will be discussed.

Internal sources of interference

The internal sources of interference in television sets can be present in our own homes. Some of the elements that can generate electromagnetic interference include:

  • Low quality LED lightingLED lamps of poor quality can generate electrical noise that can affect the TV signal.
  • Wireless router close to the TV: Proximity of the wireless router to the TV set may cause electromagnetic interference.
  • Electric motors for household appliancesElectrical appliances with electric motors, such as washing machines or hoovers, can generate interference if they are not properly shielded.
  • Thermostats and water heaters with damaged electronics: Thermostats and water heaters with damaged electronic components may cause electromagnetic interference.
  • Insufficiently insulated solar panelsIf the solar panels are not properly insulated, they may cause interference with the TV signal.

External sources of interference

External sources of interference to televisions can come from the immediate environment. Some of the most common external sources include:

  • Cars and motorbikes with poorly insulated spark plugs: Vehicles with damaged spark plugs can generate electromagnetic interference which affects the signal quality.
  • Buildings under constructionEchoes can be generated during the construction of buildings, which can affect the TV signal.
  • Poorly filtered antennas: Faulty or poorly filtered antennas can be a source of electromagnetic interference.
  • Adjacent, partially overlapping channelsPartial overlapping of adjacent channels may cause interference to the TV signal.
  • Trees obstructing the signalTrees between the antenna and the TV set can weaken the signal and cause interference.
  • Fading effect in coastal areasIn coastal areas, fading can cause signal fluctuations due to interference from atmospheric conditions.
  • Electrical fences without proper earthing: Electric fences without proper grounding can generate electromagnetic interference.
  • Birds perched on antennaeBirds roosting on antennas can affect the TV signal.
  • Bad practices when installing TV networks: Poor installation of television networks can generate electromagnetic interference.

Measures to prevent and remedy electromagnetic interference

Electromagnetic interference in TV sets can cause signal quality problems. Here are some measures that can be taken to prevent and remedy these problems.

Use of appropriate filters

An important first step is to use appropriate filters to suppress interference-causing frequencies. Band-pass filters and line filters are recommended options that help to improve the quality of the TV signal and reduce electromagnetic interference.

Ensure quality connections and cables

It is essential to ensure that all connections are tight and of good quality. Loose or damaged connections can introduce noise and signal distortion. It is advisable to use good quality cables of adequate length to avoid picking up interference.

Avoid signal overload

Another aspect to consider is to avoid signal overload. Sometimes the reception of multiple signals can generate interference. To avoid this, it is recommended to use single-channel amplifiers or better quality coaxial cables, which help to optimise reception and reduce interference.

Identify and eliminate sources of interference

It is important to identify and eliminate sources of interference, both internal and external. In the home, devices such as poor quality LED lighting, wireless routers near televisions, electric motors in household appliances, and thermostats and water heaters with faulty electronics should be considered.

On the other hand, external interference can be caused by cars and motorbikes with poorly insulated spark plugs, buildings under construction, poorly filtered antennas, partially overlapping adjacent channels, trees obstructing the signal, improperly grounded electric fences, birds perched on antennas and bad practices when installing TV networks.

Use of professional field strength meters

For a more accurate detection and resolution of electromagnetic interference, the use of professional field strength meters is recommended. These tools allow a detailed analysis of the signal and help to determine the most appropriate measures to solve interference problems.

Electromagnetic interference in DVB-T reception

The digital terrestrial television (DTT) is susceptible to electromagnetic interference that can affect signal quality and cause display interruptions or pixelation of the picture. The following will address common problems in DVB-T signal reception and provide measures to avoid such interference.

Common problems in digital terrestrial television reception

Some common problems that can affect DVB-T signal reception include:

  • External electromagnetic interference caused by nearby sources such as poorly filtered antennas, partially overlapping adjacent channels or trees obstructing the signal.
  • Fading effect in coastal areas, where the signal may be weakened due to the proximity of the sea.
  • Electrical fences without proper earthing, which can generate interference.
  • Birds perched on antennas, which can affect signal reception.
  • Bad practices when installing TV networks, which can introduce interference and affect reception.

Measures to avoid interference in DVB-T reception

To avoid or minimise interference to DVB-T reception, the following measures are recommended:

  • Use a ferrite core around the LED lamp wiring to reduce electromagnetic interference.
  • Move wireless routers away from TV sets to avoid possible interference.
  • Check that all connections and cables are in good condition.
  • Replace deteriorated electronic devices such as thermostats and water heaters.
  • Improve insulation and filtering of solar panel inverters.
  • Use single-channel amplifiers or better quality coaxial cables to improve the signal.
  • Reorient the antenna to better capture the DTT signal.
  • Conduct a field analysis with directional antennas to identify possible sources of interference.
  • Consider other ways of watching TV, such as fibre optic, satellite, cable or ADSL, if DTT reception is constantly problematic.
  • Use professional field meters to detect and remedy possible interferences.

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