More than 100 Freeview relay transmitters will have to change some of their broadcasting frequencies to avoid interference with 4G superfast mobile broadband.
Ofcom is due to auction off frequencies for 4G broadband at the end of this year, including a small chunk of the airwaves currently used by Freeview in the 800Mhz range.
Not only will 4G broadband interfere with millions of homes watching Freeview just outside its frequency range, it will also force viewers to retune across England, Scotland and Wales.
The excellent Freeview technical information blog UK Free TV has already catalogued the 33 main Freeview transmitters where viewers will have to retune.
Now webmaster Brian Butterworth has produced a list of the 100 relay transmitters which will retune, and which broadcasting channels they’ll be going to.
Relay transmitters carry a core Freeview service of around 20 channels into small areas that can't be reached by the main Freeview transmitters.
The retunes are likely to take place in 2013, although it hasn’t yet been announced whether the whole country will go in one day, or whether transmitters will be re-tuned as the mobile operators switch on their 4G service in each area.
The first 4G services on 800MHz frequencies are unlikely to go live until late 2013, depending on whether the mobile operators stop squabbling and let Ofcom get on with the auction.
The mobile operators will have to spend £180m to help Freeview viewers affected by their 4G services, from the cost of Freeview's re-tune to setting up viewers with Freesat.