Experience has shown that the lights can be a main factor in the cause of interference to radio and television services. The three most common problems are when LED lights have been used to replace halogen lamps, from fluorescent lighting with broken or poor performing chokes, or faulty street lights.
Low-voltage LED lamps can sometimes cause interference to both DAB and FM reception. This tends to happen when LED lamps are used to replace 12v halogen lamps but the original transformer is retained. The transformer has to work outside of its normal operating power which can cause electrical impulse interference. This then results in breakthrough on your radio. The more lamps switched on at the same time, the worse it becomes.
On occasion, it can be linked directly to the LED lamp being used. This can sometimes be solved by substituting one make of LED for another, but if not, it is worth trying a transformer specifically-designed for LED lamps. Mains-powered LED lamps may be less troublesome than the 12v type.
It is important to make sure that the transformer and the lamps are CE marked. Lighting equipment without a CE mark should not be on sale. Contact your local trading standards office or check the government trading standards website for further advice.
The European Broadcasting Union has a very useful video that explains how LED lights can impact DAB.
Fluorescent lights interfere with radio by emitting electromagnetic radiation. In normal operation, this is not generally obvious but as they reach their end of life it is possible they will start to emit higher levels of interference. Most good quality lights with decent suppression will not cause interference. However, if it does exist it will be seen as break up or freezing of your TV picture or clicking on your radio.
Often when these become faulty they will flash or continually turn off and on, making identification of the problem easier. However, this is not always the case. It is worth noting the time of the problem and if it starts at dusk when the lights switch on and stops when the lights switch off you have found the problem. Typical examples are the break-up or freezing of TV pictures and breakthrough on your radio.