Why some Freeview services are getting a stay of execution

The ongoing virus outbreak has destroyed the best-laid plan for many. This is also true for digital terrestrial television and moves to clear frequencies for future 5G.

This week, technical changes to the Freeview service to clear the way for more 5G services in the 700MHz frequency band were due to complete. With the UK under lockdown and it being unclear when exactly it will be possible to offer in-home support to viewers classed as vulnerable, those last set of changes have been postponed, with a lengthy delay being anticipated.

But with TV services still stuck broadcasting on 5G's future frequencies and the actual auctioning off of the frequencies to 5G companies still to come, there's little prospect of any change this year.

As a consequence, some viewers will continue to be able to enjoy some additional Freeview channels for a bit longer, as two temporary multiplexes get a stay of execution.

During 2013-14, 30 transmitters covering some of the most populated parts of the UK were upgraded to carry two additional, but temporary multiplexes - known as COM7 and COM8. They would reach around three quarters of UK households, offering extra HD channels and encouraging viewers to upgrade their Freeview receivers to HD compatible ones that supported the DVB-T2 standard.

These multiplexes currently host services including FreeSports, Forces TV, BBC Four HD and Quest HD.

The 1st May 2020 was at one point earmarked to be a possible end date of COM7 and 8. Then it was agreed that the multiplexes could move and remain on-air using a small section in the middle of the future 5G frequency band - the centre gap between downlink and uplink frequencies - enabling them to stay on air a little longer, at least until mobile companies were ready to use the centre gap.

As it stands now, COM7 and COM8 will continue, but Arqiva, the company operating the multiplexes, will get three month's notice of a mobile company wanting to start using the centre gap. Additionally, Arqiva will have to terminate broadcasts if the TV broadcasts interfere with the new 5G services. There's no worry of that happening anytime soon given the delay in deploying 5G on TV frequencies.

Preparations for 5G arriving have been made though: in order to maintain a guard between 5G and the temporary multiplexes in the centre gap, a 167kHz offset is applied to multiplex COM8, which carries channels including FreeSports and BBC Four HD. This has reduced the amount of bandwidth available. To ensure reception of the multiplex remains robust, the forward error correction was changed to 1/2 earlier this year, which in our observations has made the signal slightly more reliable than before the change.

And following on from a number of channel changes in recent years, notably from Sony's decision to move many of its services to lower coverage multiplexes, some spare capacity elsewhere on Freeview has been taken up by channels previously on COM7 and 8.

PBS America, Together and Smithsonian Channel have thereby secured a longer term future on Freeview and become more widely available to Freeview viewers in the process of doing so.

This leaves Now 80s, Forces TV and FreeSports continuing for the time being on temporary capacity.

Most other channels that still reside on that temporary capacity are +1 channels, which are seen as easily expendable when the switch-off occurs.

There's more doubt about what will happen to the BBC's HD service: when the BBC launched HD versions of many of its smaller channels in 2013, there was insufficient capacity for all of them to sit on a BBC multiplex. Therefore BBC Four HD, BBC News HD and CBeebies HD were launched on the temporary capacity of COM7 and 8. With improvements to encoder technology, it's possible to see at least one more HD service added to BBC capacity, but with the BBC facing pressure to make more cuts to services and internet distribution becoming more important, there's no guarantee the linear BBC HD service will remain the same.

4seven HD and Channel 4+1 HD (only in SD on cable and satellite) on COM7 are prime candidates for the axe, given Channel 4's current financial situation, following a drop in advertising sales.

Meanwhile, for the HD outlets of Quest and QVC on COM8 to continue, Ofcom, Digital UK/Freeview and multiplex operators would need to confirm a plan to convert existing Freeview capacity to DVB-T2, as was once envisaged. As it stands, there wouldn't be any space left once the temporary multiplexes have closed to keep them running, forcing viewers back to standard definition.

With these services being offered a stay of execution due to the delays in clearing TV frequencies and deploying new 5G services in their place, there's plenty of time to plan ahead to ensure Freeview doesn't go backward on HD.

  • Contributed by Mike Manning, who was the editor of the former a516digital website until early 2019, monitoring and reporting on the post-switchover development of digital terrestrial television in the UK.