It is possible that a specific part of a solar panel system, the inverter, can cause interference if not properly shielded. A solar panel inverter like any other electrical device in the home can produce interference. Therefore, it is important that this is fitted correctly. If you think your solar panel is the cause of your interference a qualified installer should be able to run some tests to establish if this is the case.
If you are using a loft aerial and install solar panels on your roof, it will significantly reduce reception.
A solar panel inverter will produce some electromagnetic radiation and potentially interference, especially if it is incorrectly fitted during installation.
An inverter converts the DC power produced by solar panels into AC power which is used by your household equipment. The inverter typically use switching techniques to convert the power, and this can cause interference if the inverter is poorly designed and not shielded. The problem with inverters is that they create broadband noise which can be generated over a very large frequency range. Therefore they can affect both television and radio reception. It is also possible that it can cause interference to your neighbours, as the cable that runs from the inverter to the solar panel can be very long and this can act as an aerial radiating the interference over a large distance.
It is therefore important to ensure you purchase good quality equipment that has been installed by a suitably qualified installer. They should run some tests with you after installation to ensure no interference is present to either your radio or television.
An aerial in the loft would have significantly reduced reception if the roof is covered in glass and metal. The best place for an aerial is outside on the chimney stack, if you have one, to get the best possible reception. Every object a digital signal has to pass through will reduce its strength by approximately 20%. Therefore, if your signal is already weak, fitting solar panels will make it worse if the aerial is in the loft.