Arqiva engineers have worked around the clock over recent weeks to deliver this as the latest step in restoring services following the fire at Bilsdale in August.
The switch-on means that viewers will need to retune TVs and a guide on how to do this can be found here.
Additional engineering works are taking place throughout the day today (Wed Oct 13) so Arqiva recommends doing this after 5pm today.
A spokesman added: "As we have previously said, not everyone is covered by the switch-on.
"And further details on help for those whose TV services are still affected from this evening will be set out at bilsdalemast.co.uk tomorrow (Thurs Oct 14).”