Freeview viewers in Strathspey, Morayshire and parts of Easter Ross may need to retune their TV equipment on August 23 to continue watching programmes.
Some Freeview channels are moving to new airwaves to allow for the future development of new mobile broadband services.
Following a decision by Ofcom, the media regulator, transmitters across the UK are being updated region by region as part of a major engineering programme being carried out between now and 2020.
Changes will begin at the Knockmore transmitter group shortly after midnight and Freeview channels will be off-air overnight until 6am. After this, any viewers receiving their TV signal from the main Knockmore transmitter who find they are missing channels can retune to get them back. Services from smaller local relay transmitters will be subject to disruption until mid-afternoon.
Satellite and cable TV are not affected.
Around 42,000 homes are served by these transmitters.
Freeview will be running an information campaign to prepare people for the change, including advertising and on-screen messages.
Retuning should be straightforward and some TV equipment will retune automatically.
Anyone who needs advice, or who finds they are still missing services after retuning, can visit the Freeview website at www.freeview.co.uk/tvchanges or contact the Freeview Advice Line free on 0808 100 0288.
Some older aerials may need to be replaced to continue receiving all channels. Help will be available for viewers where this is the case.3
Further information is available online at www.freeview.co.uk/tvchanges