Freeview users across Tayside and Fife will need to retune their TV equipment as local airwaves are cleared for the roll-out of faster mobile broadband.
Technical changes at the Angus transmitter group, which serves 210,000 homes, will free up frequencies for the future introduction of fourth-generation mobile services.
Between now and the end of the year, similar upgrades will be made in other areas of the UK to prepare for 4G.
TV services will be subject to disruption from midnight on April 17 as channels including BBC One, ITV, Channel 4, Channel 5, Film4 and Yesterday are moved to new frequencies.
Work at the main Angus transmitter is expected to be completed by 6am and viewers can retune at any point after this. Services at other local transmitters may be off-air until late afternoon.
Once these resume, anyone missing channels should retune their TV or digital box to get them back. Digital UK is launching an information campaign to make viewers aware of the need to retune, including local advertising and messages on screen.
Digital UK chief executive David Scott said: “It’s a good idea to retune your Freeview TV or box regularly to make sure your channel list is up to date.
“It usually only takes a few minutes.”
Viewers can check if they need to retune and the TV services predicted to be available at their address by using the coverage checker at digitaluk.co.uk.
Detailed advice on retuning is also available from Digital UK’s website and advice line on 08456 505050.