4G mobile signal will interfere with UK's digital TV

The digital television signal for hundreds of thousands of UK homes will be affected by interference from 4G mobile networks when they come on-line in 2013, the telecoms regulator has warned. Ofcom said mobile operators should bear the estimated £100 million (Dh603 million) costs of reducing the interference, after they bid for 4G spectrum early next year. It estimates that about 3 per cent of digital terrestrial television viewers, about 760,000 homes, will be affected when the so-called "digital dividend" spectrum, previously used for analogue broadcast, in the 800MHz range starts being used to transmit mobile phone calls and data in the next few years. The interference problem adds another complication to the process of the digital TV switchover, which is due to be completed in 2012. "It is an issue but it is not insurmountable," said Ofcom. "There are plenty of mitigations to ensure everyone can continue watching TV." One person at a mobile operator said homes in north-west England were most likely to suffer the interference. The problem will be most acute for TVs tuned to channel 60, at the higher end of the digital terrestrial television broadcast range, which is adjacent to the portion of the airwaves given over to 4G. Ofcom believes the vast majority of the 760,000 homes affected will be able to fix the problem by fitting a filter to their TV aerial, a £10 device that could be installed without the need for an engineer. Imperfect solution However, for about 30,000 homes, filters will not solve the problem. Small indoor aerials attached directly to the TV set may also find it more difficult to cope with the interference than outdoor receivers. Ofcom has estimated that £20 million will be required to pay for all the filters and £33 million for installation. In cases where filters do not help, Ofcom said that a "last resort" would be to offer the affected TV owners another way to receive the digital signal, such as Freesat, although this could cost up to £10 million. Mobile operators in affected areas will also need to make adjustments to their masts, costing an estimated £11 million.