Freeview viewers in parts of East Sussex may need to retune their TV equipment to continue watching BBC programmes soon.
Channels are moving to new airwaves to allow for the future development of new mobile broadband services.
This comes as 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 Dover transmitter group in the morning and are expected to be completed by 10am on August 22.
After this, any viewers receiving their TV signal from the main Dover transmitter who find they are missing BBC channels can retune. Services from the Margate transmitter will be subject to disruption until late afternoon. Satellite and cable TV are not affected.
Around 220,000 homes are served by the affected transmitters. Freeview will be running an information campaign to prepare people for the change, including advertising and on-screen messages.
Further changes will take place on October 16 as other channels, including ITV, Channel 4 and Channel 5, complete the move to new frequencies. On-screen messages will remind viewers to retune.
A spokesperson for Freeview said, “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.