Rai is planning to extend DAB+ services to the most important Italian urban areas and to the motorways (including service continuity in tunnels). Radio service transmission inside tunnels requires methods such as the installation of radiating cables (“leaky-feeders”) along the tunnel ceiling. This approach is costly, thus leading RAI Research Center to investigate the feasibility of an alternative approach using direct RF irradiation by means of antennas positioned outside the tunnels (not far from the entrance) or internally.

In October 2016, at the Laboratory of Rai CRIT, it was carried out a series of tests on the demonstrator for time synchronization and frequency alternative to GNSS (Global Navigation Satellite System), developed by Antares S.c.ar.l under the European Demeter project, in collaboration with INRIM.
The tests have allowed us to evaluate the behavior of the developed system, especially in reference to the specific needs for synchronization of a network of DTT transmitters in single frequency (SFN).

The Research Center, after experimenting in the laboratory the first prototypes of DVB-T2 lite, activated in Aosta Valley a single frequency network  on UHF channel 53 in order to test the potential offered by the new system . The scheme chosen for the testing involves the use of “mixed” system: the T2 signal is split into two sub frames, one compatible with the standard T2 base, the other T2 lite, optimized respectively for fixed and mobile reception . The four transmitters of Gerdaz, Salirod, Arpy and Courtil radiate a bouquet consists of three HD programs for the T2 base and from one to three services oriented to mobile reception for the T2 lite.