The migration of BBC Four HD (high definition) and CBeebies HD to the PSB3 Freeview terrestrial multiplex has been delayed. With the temporary COM7 multiplex having now closed, these channels are currently unavailable, with information slates on the respective channel numbers advising of their imminent return.
This issue is relates to a capacity issue on the PSB3 multiplex. In its current form (or at least its form when the COM7 multiplex was in operation), there is no vacant space (or bandwidth) available to broadcast BBC Four HD and CBeebies HD.
BBC Four HD and CBeebies HD timeshare, with CBeebies HD running from 6am to 7pm, with BBC Four HD taking over from 7pm (in similar practice to how the standard definition versions broadcast on the PSB1 multiplex). Therefore, to enable both channels to broadcast, a single 24 hour video stream is required
This means that in order for both channels to broadcast on the PSB3 multiplex, either an existing channel needs to move or close, or technical changes need to be made in order to free up sufficient space for the video stream. The BBC, who control this multiplex, have opted for the latter, and it is these changes that were not made in time before the COM7 multiplex closed.
As yet, no completion date has been given for when these changes will be made.