Freeview users in County Durham and Tyne and Wear have been warned they may need to retune their TV equipment to continue watching BBC programmes.
Certain Freeview channels are moving to new airwaves to allow for the future development of new mobile broadband services.
Following a decision by the UK Government, transmitters are being updated region by region as part of a major engineering programme being carried out between now and 2020.
The required changes will take place at the Pontop Pike transmitter - situated between Consett and Stanley - on the morning of September 12 and are expected to be completed by 10am.
After this, any viewers receiving their TV signal from here who find they are missing BBC channels can retune. Satellite and cable TV are not affected.
Approximately 660,000 homes are served by the affected transmitter. Freeview will be running an information campaign to prepare people for the change, including advertising and on-screen messages.
Further required changes to Freeview channels will take place on November 13. On-screen messages will remind viewers to retune at this time.
Retuning should be straightforward and some TV equipment will retune automatically. Some older aerials may need to be replaced to continue receiving all channels.
Viewers may be eligible for free in-home support, including aerial work if needed.
Anyone who needs advice, or who finds they are still missing services after retuning, can visit the Freeview website , or contact the Freeview Advice Line free on 0808 100 0288.
