Freeview changes for BBC Four HD and CBeebies HD


UPDATE | BBC Four HD and CBeebies HD are moving to new Freeview bandwidth, requiring viewers to retune to continue watching.

Both services continue to have limited coverage on Freeview, compared to other BBC HD channels.

The BBC has confirmed that both services will move during the course of the 11th January 2018, after which viewers should retune. Some devices will process the changes automatically. By the 17th January, viewers who haven't retuned will lose access.

Users of EE TV and YouView boxes (for BT TV, TalkTalk TV, Plusnet TV) as well as Now TV Smart Boxes are also affected by the changes.

Sky, Freesat and Virgin viewers are not affected.

Both channels share Freeview bandwidth on a timeshare basis, with a switchover at 18:57 each day. Due to a lack of available bandwidth on its own Freeview capacity, the BBC has been using capacity from commercial multiplex operator Arqiva to make the services available to Freeview audiences. However, Arqiva's HD coverage of around 75% of the UK means fewer households are able to receive BBC Four HD and CBeebies HD as well as BBC News HD (which is not changing) on Freeview, compared to its other channels, which reach over 98% of households. The services are moving from multiplex COM7 to COM8 - or from one of Arqiva's HD multiplexes to another.

Where available, BBC Four HD is carried on Freeview channel 106, while CBeebies HD is assigned channel 205. 

It is understood that the change is linked to preparations for Freeview frequency changes that will start to take place across the UK on a region-by-region basis (except Northern Scotland) between February 2018 and mid-2020, which is affecting the amount of available Freeview bandwidth.

Another retune will be required soon...
The forthcoming frequency changes mean that for some viewers, including those in the West Midlands and London, an additional retune will be required in the coming weeks to continue receiving all available Freeview HD channels, including BBC Four HD and CBeebies HD.


Other parts of the UK will be affected at a later date.


Tech analysis
a516digital editor Mike Mannng comments:
The changes affect two services broadcast on Arqiva's HD multiplexes. As part of a move by Ofcom to clear the 700MHz frequency band for future 5G mobile services, Arqiva's HD multiplexes will be moved to a temporary single frequency network on UHF channels 55 and 56 on a region-by-region basis, starting from February 2018. For the first time, neighbouring Freeview transmitters will carry the same services on the same frequencies. Under normal circumstances this would cause co-channel interference, particularly in overlap areas where signals from multiple transmitters would destroy reception. As a result, a parameter called the guard interval is being changed (from 1/128 to 1/16) on the affected multiplexes to ensure this doesn't happen. This is now due to take place around 25th January, subject to final confirmation. However, the trade-off is that the available bandwidth is reduced - expected to be by around 3Mbps per multiplex. A reduction of bandwidth means there's less room for as many channels to broadcast on a multiplex, so something has to move. Arqiva's COM7 multiplex, which carries the affected BBC HD services will be full after the switch based on the services it carries now. However, with space still available elsewhere, it provides an opportunity to conduct some load balancing, moving channels like BBC Four HD to where there's still some room.


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