Have you ever tuned in to your favourite radio programme only for it to be drowned out by another station?
This could be caused by interference from a pirate radio station broadcasting illegally over the airwaves.
They're a particular problem in larger cities such as London, Birmingham, Leeds and Manchester.
But they're not just a nuisance to listeners.
Pirates frequently install homemade radio transmitters on the top of high rise tower blocks, disrupting the lives of residents and causing thousands of pounds worth of damage to public property.
And as well as interfering with legitimate stations, they can also disrupt the vital communications of the safety of life services, particularly air traffic control.
Ofcom takes enforcement action against illegal broadcasters to resolve interference problems and takes repeated actions to remove pirate stations, including raiding studios and seizing equipment.
Listeners play a big role in helping us to tackle the problem of pirate radio.
If you've experienced interference from a pirate radio station, please complete our online form
It's important to remember that anyone involved with illegal broadcasting is committing a criminal offence and may be arrested by police.
That includes someone who allows their premises to be used for illegal broadcasting or advertises on a station.
The maximum penalties are an unlimited fine and two years in prison.