With the development of DAB comes the question of how to add services to an existing system. A study conducted in Italy in 2017 by the RAI-Radiotelevisione Italiana Research Centre, in anticipation of the development of digital radio, highlighted the criticalities of using the structures built to broadcast the channel over Isoradio traffic. It would be necessary to intervene on the device that mixes the signals before conveying them on the slit cable: a costly and complex operation. It was therefore suggested, in order to drastically reduce costs, to use the radio wave system by re-transmitting the signal from an antenna placed at one end of the tunnel, or, in longer tunnels, at both ends.
A leading country…
Italy, due to its orography, is the second largest country in the world in terms of the number and length of tunnels, second only to China and followed by Japan, Norway, Switzerland, Austria and France. And it can count on world-leading companies in tunnelling, underground construction and transmission systems with a high level of integration such as those used in the Frejus (12.8 km) and Mont Blanc (11.6 km) international motorway tunnels. More than 30 channels are available in these tunnels for the services of Italy and France: fire brigade, border police, Carabinieri, Gendarmerie, medical emergency vehicles and FM broadcasting with RDS. The systems are managed by a control centre that can interrupt radio programmes to broadcast emergency messages.
…but Switzerland also has its leadership
Switzerland is well advanced on DAB. Network expansion has been going on since 2014: the country had given itself a ten-year horizon for the switchover to digital radio, which will take place at the end of 2024 when the analogue FM transmitters will be switched off. Currently, SSR network coverage for indoor reception is 98%, while for outdoor reception and car radios it even exceeds 99%. Today, therefore, Switzerland boasts the best DAB+ coverage in the world, with some 193 tunnels longer than 300 metres being illuminated by the signal already in 2018 with an investment of around CHF 30 million. The areas not covered are mainly located in peripheral regions, a problem that will be solved in the coming years. (Writteb by Fabrizio Carnevalini)
Despite the fact that DAB+ signals already reach 99 % of the population in Switzerland, as required by the Federal Office of Communications (OFCOM), the public broadcaster has further expanded the digital network in Italian and French-speaking Switzerland. Between 2020 and 2021, ten new transmitters were activated and twelve others were optimized. Improvements were made in the cantons of Jura, in the northwest of the country, and Ticino, located almost entirely south of the Alps, where the network was further expanded at the beginning of 2021 with the activation of the installation in Cardada. In Switzerland, the digital signal is also broadcast in tunnels longer than 300 meters: the list of the 193 road tunnels covered by DAB+ signals can be consulted on broadcast.ch.
More than 60,000 Swiss citizens have signed a petition to hold a referendum to block the switch-off of FM radio channels, scheduled to start in 2022. Switzerland was following in the footsteps of Norway, which was the first country to choose to migrate to Dab in 2017 (although there are currently more than 100 FM radio stations and 552 transmitters on air in the Scandinavian country). The initiative’s promoters cite an article published in the Neue Zürcher Zeitung by media expert Urs Saxer, which states that SRG SSR, as a public service, has a clear mandate to guarantee a basic service to the entire population, and switching off FM would have no legal basis. The switchover is planned to take place in two stages: the public broadcaster SRG SSR will switch off its transmitters in August 2022, while the private broadcasters will have time until January 2023. According to a survey conducted last year by the Swiss branch of the market research institute GFK, only 29% of Swiss listen to terrestrial radio (FM and/or DAB) and only 13% of the Confederation’s citizens use analogue FM radioonly.