Portugal has started using Multi Frequency Network (MFN) in an attempt to resolve DTT reception problems in parts of the country.
The move follows the request of DTT network operator, PT Comunicações, (PTC) for licensing four transmitters (Marofa, Mendro, Palmela and São Mamede) on alternative frequencies to those operating in mainland Portugal, subsequently approved by the National Communications Authority (Anacom). Previously, DTT channels were transmitted in Single Frequency Network, i.e. on a single channel (channel 56, between 750 MHz and 758 MHz).
Anacom believes that the new network configuration, which divides mainland Portugal into twelve regions that receive DTT on different frequencies, could resolve reception problems. The regulator estimates that around 60 per cent of the population is covered by PTC’s seven existing MFN transmitters, which include the four recently licensed.
Officially, the migration from SFN to MFN in Portugal should start in 2016 and end in 2017, when the frequencies in the 694-790 MHz band are released. Some 900.000 households will be affected by the change, as they will have to re-tune their STBs and re-orientate their antennas – these additional costs will be covered by PTC.
Meanwhile, the regulator is considering the application of penalties against PTC due to DTT coverage problems which it considers as “grave and unacceptable”. Measurements by 46 newly installed probes in the period between 14 and 20 July detected “numerous and prolonged interruptions” of DTT transmissions in the districts of Beja, Braga, Bragança, Castelo Branco, Setúbal, Faro, Aveiro, Leiria and Porto. The probes are part of a network of 400 probes for measuring the DTT signal that Anacom started installing in 2013.
PTC has challenged the validity of the data recorded by the 46 probes, claiming that data from four of its own probes indicate that the DTT transmissions are within the normal limits.