The last phase of switchover takes place on 31 March
The last part of Wales still receiving analogue television signals is starting the switch to digital broadcasting.
The Wenvoe transmitter serving 649,000 homes in Cardiff and south east Wales will cease broadcasting BBC Two in analogue, and a new signal begins.
Digital TVs and set-top boxes will need to be retuned once the switchover begins early on 3 March.
The First Minister unveiled a clock counting down to 31 March, when the remaining channels will be turned off.
HOW TO RE-TUNE YOUR TV
Switch on digital box/TV
Press 'menu' on remote control
Select 'set-up' or 'installation'
Select 'first time installation' (sometimes called 'factory reset', 'full retune' or 'default settings')
Press "OK" if equipment asks if you want to delete all channels
Channels will be automatically installed - equipment may restart
Source: Digital UK
Wales will then become the first digital nation in the UK.
The switchover in Wales began last August in Swansea, which became the first fully digital city in the country.
Mid and north Wales followed, with the south east the last region to be converted.
The switchover is being managed by Digital UK, which said before the process began, one in three people in Wales could not receive Freeview services.
The switchover is likely to take a number of hours to complete, as Wenvoe and its 75 relay stations are altered, and terrestrial TV services will be off-air for some viewers until the switch is complete.
Once services are back on-air, viewers using Freeview, BT Vision and Top-up TV will have to retune their sets.
On Wednesday morning, First Minister Carwyn Jones will unveil a digital countdown clock in Cardiff, which will mark the time until the remaining analogue signals are switched off, and Wales becomes a fully digital nation.
The countdown clock will be taken to other towns and cities in the south east, including Newport, Merthyr Tydfil and Bridgend to remind people that switchover is almost complete.