Radio, TV or WIFI interference with LED lamps
There are many factors in an LED lamp installation that may impact radio, TV or WIFI signal reception leading to partial or complete loss, especially in areas with low signal strength. Changing to another brand of LED lamp will not necessarily solve reception problems.
Why does this happen?
Electromagnetic compatibility is a system issue and is affected by many variables in the installation. Despite testing for compliance with EMC standards a real life installation will be different from the standard test conditions and reception problems can result. These problems are very likely to arise from the power supply or the wiring and not necessarily from the lamps themselves. The possibility of reception problems also increases dramatically in situations where the signal strength is poor or receiving equipment is low quality.
The likelihood of a problem is greatest when directly replacing 12V halogen lamps with LED lamps. It is not possible to design a 12V LED lamp that will remove the possibility of interference when retrofitted on AC transformers because the AC transformer is the most likely source of the interference, with output frequencies varying hugely from 10’s to 1000’s of Hz. The AC transformer will have been designed with a large resistive load in mind and not a light inductive load and so its characteristics can change when the load type changes
Most of these factors are outside of the lamp designers control and LED lamps are not the only and not necessarily the most dominant disturbance source in the system. The power supply is the biggest source of possible interference, especially if not originally designed for use with LED lamps. Issues should be solved on a system level and changing system variables other than the lamp may lead to improvement.
- Change to dedicated DC LED drivers or mains voltage lamps as these are less likely to lead to reception problems; the use of LED lamps with legacy AC transformers is only a transitory phase in the adoption of LED lighting enabling many customers to benefit from LED lighting with minimal investment.
- Minimising cable lengths will reduce emissions.
- Use shielded cables.
- Add EMI filters or chokes at the input and output of the transformer. These ferrite rings are commonly available to clip over the cable.
- If possible, position aerials as far from sources of interference as possible and connect to receiving equipment with coaxial cables.