Digital TV viewers in South Wales will be required to retune their Freeview boxes, as the principality prepares for the wider launch of 4G mobile broadband.
Next-generation mobile services are set to launch in the 800MHz and 2.6GHz frequency bands in the first half of 2013.
And this requires the local airwaves to be cleared - bringing about technical changes to the Wenvoe transmitter in the Vale of Glamorgan, reports the BBC.
TV viewers can retune their boxes at any point, but only those receving a signal from the Wenvoe transmitter will be affected.
David Scott, Chief Executive of Digital UK, said it is a "good idea" for TV viewers to retune their Freeview TV or box regularly to make sure the channel list is up to date.
"It usually only takes a few minutes but if anyone is unsure what to do, there's plenty of information available on our website or from our advice line team," he stated.
The first 4G mobile broadband services launched in October across 11 UK cities, including Cardiff.