£180 million: the cost of protecting TV viewers from 4G interference

The winners of the forthcoming 4G auction will need to stump up £180 million to protect terrestrial TV viewers from interference, it has been revealed by Communications Minister Ed Vaizey.

4G, which will bring very high speed mobile internet across the world, will be using frequencies that are still being used for TV in the UK.

TVs and many TV aerials are designed to receive signals transmitted across the UHF band, UHF channels 21-68. UHF channels 61-68 (part of the so-called 800 MHz band) are to be used for 4G. This means that households close to a 4G device or base unit will suffer interference, as the the aerial and TV would be capable of receiving those frequencies. This may overload the tuner inside the TV and could cause break up of TV signals. (Even now, some current mobile phones using the nearby 900 MHz band cause trouble when located near a TV, often creating a da-ta-da, da-ta-da, da-ta-da style noise).

The solution is for the successful operators of the 4G network to pay for filters blocking reception of the top of the UHF band to be installed in affected households - around one million households in total, where households are close to a 4G mast.
BBC News reports that: "Homes falling within a certain range of transmitter towers will automatically have a filter issued, while a helpline will be set up to deal with interference cases outside of the predicted areas."
Filters are to be installed to digital boxes or TVs. Help will be provided for the elderly and disabled.

According to the Department for Culture, Media and Sport (DCMS), for an estimated 10,000 households a filter will not be enough -  they will need to be switched to cable or satellite services. 4G operators will also be expected to foot the bill for the switch to cable or satellite. Ironically, these households will probably be in a good position to stream live TV via the 4G network - although this won't be free.

There will still be a few households that can't have cable or satellite. These households will be given £10,000 to "find a solution". The DCMS assures that such households will be given advice on how to spend the money to get TV services back. An option may include the laying of fibre optic cables to the affected households.

More complications ahead?
Earlier this week, an agreement was signed that allowed the 700 MHz band to be converted to mobile internet access across the Middle East and Africa. The 700 MHz band is also to be used for mobile internet in the Americas. We may at some point see pressure on the UK and other European countries that use the 700 MHz band for digital TV to convert more frequencies for mobile use, to reach global harmonisation. This can't be done unless all Freeview services transfer to the DVB-T2 standard used for HD broadcasts, which would allow more standard definition services to fit on one digital multiplex, thus using less frequencies. (Taking away the 700 MHz band would leave just UHF channels 21 to 48 in use). That would make all standard definition only Freeview devices redundant and the operators would need to buy some new  filters for both 700 and 800 MHz bands for us all...

The 800 MHz frequency band to be used for 4G, currently forms the upper end of the UHF TV frequency band, containing UHF channels 61-68. Ofcom originally anticipated that the top end of the UHF band could be used for mobile services, so that the original switchover plan saw UHF channels 63 to 68 being cleared at switchover stage 2 or shortly thereafter, where transistional frequency arrangements were neccessary.

This meant that transmitters such as Winter Hill (Lancashire, ITV Granada region), Waltham (Leicestershire, ITV Central East region) and Tacolneston (Norfolk, ITV Anglia East region) had to surrender use of some frequencies at stage 2 of the switchover.

However in the years following the development of the original switchover plan, international consensus was reached to clear the whole 800 MHz band from UHF channel 61 upwards. This meant that where UHF channels 61 and 62 were being used after switchover, a further retune would be needed to get Freeview off these UHF channels. Where possible, switchover from late 2011 onwards incorporates a total clearance of UHF channels 61 upwards, not just UHF channel 63 upwards.

Transmitters such as Waltham and Mendip (Somerset, ITV West region) that saw use of UHF channel 64 end in 2011 and 2010 respectively, are still using UHF channel 61. Ofcom has decreed that wherever possible all services on UHF channel 61 should be moved to UHF channel 49 and any services on 62 be moved to 50. In turn services on UHF channels 49 and 50 are moved down to 39 and 40. Sutton Coldfield's HD multiplex as a result appeared on UHF channel 40 and not the originally proposed channel 50 at switchover stage 2 last year.

UHF channels 39 and 40 were originally cleared at switchover for a potential auction of a portion of the 600 MHz band, but 39 and 40 are not going to be part of this auction any more, and pressures to clear the 700 MHz band may result in part of the freed up 600 MHz band, between UHF channels 31 and 37 being used to accomodate services from the 700 MHz band rather than for new TV multiplexes.

Whatever does happen next, one thing is for sure: we need TV manufacturers to stop building TVs with tuners designed for the top of the UHF band and more aerials to be manufactured that are not suitable for 800 MHz band reception.

Also on this subject:
BBC News report

As reported in the Daily Telegraph.
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