Wednesday will see the analogue TV signal from the Wenvoe transmitter switched off completely and replaced with a digital one.
The historic event means viewers across Caerphilly County Borough will be able to pick up the full range of digital channels.
After the first phase of switchover homes in the region no longer get BBC 2 through their analogue aerial and can get the BBC’s digital package.
The change means S4C will become an all-Welsh language channel and viewers should be able to get Channel 4.
After Wednesday viewers will only be able to watch television if they either have a digital set top box or digital-ready television.
Viewers with Sky will be unaffected.
To draw people’s attention to the changes, S4C has been staging a circus-themed roadshow called On with the Show, featuring contemporary circus performers NoFit State Circus.
The events have been hosted by some of the channel’s best-known presenters, including Nia Parry, Gareth Roberts, Daloni Metcalfe, Dudley Newbery, Angharad Mair and Morgan Jones.
Tim Hartley, S4C’s head of corporate affairs, said: “The digital switchover is a very important stage in S4C’s evolution because soon we will be an entirely Welsh channel.
“We value our viewers and we have been staging the On with the Show campaign in the heart of communities since the start of switchover, to offer support and advice, and to demonstrate that switching to digital isn’t difficult – certainly not as difficult as learning tricky circus skills.”
For more information about S4C’s digital switchover visit www.s4c.co.uk/digital
For more information about digital TV in general visit www.digitaluk.co.uk