UPDATED Ofcom has today confirmed it's taking away more of the Freeview TV frequency band for use by mobile broadband services from the beginning of the next decade.
The regulator has pledged to secure the last remaining TV frequencies for use by Freeview without the need for another 'switchover'.
The decision allows mobile network operators to deliver mobile broadband using some of the frequencies currently used for digital terrestrial TV services, such as Freeview, and wireless microphones. An auction to determine which operators will take over the 700 MHz band will take place later this decade.
These frequencies make up the 700 MHz frequency band. The 800 MHz was handed over to mobile network operators in 2013, when in the summer the last Freeview services in Scotland were moved out of the band.
Ofcom says consumers and businesses "should get faster and cheaper mobile data services" as a result of the frequency re-allocation, although that may realistically depend on whether the same few mobile network operators snap up the extra frequencies.
Ofcom’s objective is to make this happen by the beginning of 2022, and possibly up to two years earlier.
Users of wireless microphones in the programme making and special events (PMSE) sector, such as theatres, sports venues and music events, also use some of the affected frequencies. Ofcom says it will ensure that they continue to have access to the airwaves they need to deliver their important cultural benefits.
The move to clear 700 MHz from TV started in countries such as the USA, and in the meantime most of the world has pledged to use 700 MHz for mobile broadband services. Mobile network operators are keen to use these frequencies, as they penetrate buildings better and serve a wider area than their services on traditional mobile phone frequencies.
What does it mean for viewers?
For viewers, it will mean that many more will need special filters installing to block interfering signals from the mobile services, as the changes will bring mobile broadband services even closer to more of the UK's terrestrial TV frequencies.
In addition, Freeview users in many areas will need to retune at the appointed time for their region (yet to be determined) when TV services will need to move down to lower frequencies. Newer Freeview HD devices and YouView boxes have been designed to make the retuning experience easier. Some services may only be available with a Freeview HD device or YouView box.
Ofcom has indicated that if there continues to be "medium to high demand" for Freeview capacity in the coming decade, further multiplexes will have to transfer to DVB-T2, meaning older Freeview boxes won't receive some channels.
There is little chance of Ultra HD services having enough capacity to launch on Freeview, with satellite, cable and IPTV services likely to become the focus of UHD in the 2020s. However, there is sufficient capacity to allow further channels to migrate to HD transmission.
The impact of 4G
Currently, some households in areas where 4G has launched right next to local Freeview frequencies, such as parts of Brighton, have had to get a filter to reduce interference. At present the impact has been limited, with market leader EE's 4G service primarily using frequencies further away from Freeview, and roll-out of 4G on the frequencies nearer to Freeview in its early stages.
Mobile network Three has been allocated the 4G frequencies closest to Freeview frequencies, but is the furthest behind rolling out 4G at 800 MHz.
At800, an organisation set-up by mobile network operators to mitigate inference to Freeview from mobile signals is responsible for providing affected households with one free filter.
Many TV aerials are designed to receive the full TV frequency range, including the 700 and 800 MHz frequency bands. As aerials are not replaced that often, it will take a long time before all TV aerials on rooftops are changed over to variants that are only optimised for the remaining part of the Freeview TV frequency band.