The regulator outlined its plans for a substantial chunk of the UHF frequency band in a statement today.
Under current plans, local TV services are scheduled to launch in the coming two years using locally spare frequencies (geographically interleaved spectrum) on the TV band used for existing Freeview services. They will appear on Freeview channel 8 (or 45 in Scotland and Wales) for viewers within range of the local TV multiplex signal.
However, the vast majority of local TV stations are due to launch on a local TV digital multiplex that has been allocated a frequency in the 700 MHz band that Ofcom has now earmarked for clearance, subject to international co-ordination.
Local TV viewers would need to retune to continue watching their local channel when the changes occurred.
As it stands, 700 MHz clearance would affect local TV services in the following locations and transmitter sites:
- Birmingham (Sutton Coldfield transmitter)
- Brighton and Hove (Whitehawk Hill)
- Bristol (Mendip)
- Cardiff (Wenvoe)
- Edinburgh (Craigkelly)
- Glasgow (Black Hill)
- Leeds (Emley Moor and Beecroft Hill)
- Liverpool (Winter Hill petal 2)
- Manchester (Winter Hill petal 1)
- Newcastle (Pontop Pike)
- Norwich (Tacolneston)
- Oxford (Oxford/Beckley)
- Preston (Winter Hill petal 3)
- Sheffield (Tapton Hill)
In addition, the frequency currently used for the Manchester TV Network of additional Freeview channels is in the range earmarked for clearance.
In its statement, released today, Ofcom noted that in a recent consultation on the future plans for the use of the UHF frequency band, there had been no responses from the "local TV community". * It admitted - without providing any detail on possible alternative frequencies - that the "change of use of the 700 MHz band to mobile broadband use would reduce the amount of geographic interleaved spectrum available for the services relying on it. However, this reduction could be mitigated through achieving the objective of seeking to ensure that DTT has an amount of spectrum available to it that enables it to continue to deliver the benefits it currently provides."
Meanwhile, Ofcom is yet to award a licence to a local TV multiplex operator, who would be responsible for running the infrastructure to bring local TV to viewer's TV sets at the time of the proposed clearance exercise.
Currently, Avanti, the BBC, CoMux UK and Local TV Multiplex Ltd are in the running for the licence. The reduction in the availability of suitable frequencies for local TV may curtail any multiplex expansion plans to new towns and cities beyond the first phase of local TV channels going on air during 2013 and 2014.
Ofcom advised potential multiplex operators in May that "although the likelihood of this is low in the immediate future, there could be changes to the use of the UHF band in the longer term that may result in Ofcom having to change or even revoke some of the frequency assignments for this local multiplex service."
The clearance plans could hasten a switch to the newer digital terrestrial television standard DVB-T2 during the course of the licence period of the multiplex operator in order to enable services to utilise 'single frequency networks' (SFNs) in locations such as Leeds, where the local TV channel has currently been allocated two frequencies to cover the City.
DVB-T2 - which offers better technical parameters for low powered, single frequency networks - is currently being used in Northern Ireland to broadcast a low power, three channel multiplex carrying Irish TG4, RTÉ One and Two as well as for the UK-wide Freeview HD multiplex.
* paragraph 5.33