Organization of single frequency DRM digital radio broadcasting networks. Features and results of practical tests

The Digital Radio Mondiale (DRM) broadcasting standard is the only ITU approved for worldwide application in the frequency range below 30 MHz. The DRM standard provides the use of single-frequency synchronous broadcasting networks. Their application with competent frequency-territorial planning allows to increase the efficiency of the DRM broadcasting networks, as well as to save the frequency resource. The DRM single-frequency synchronous networks construction in general differs from the DVB-T/DVB-T2 synchronous digital television networks or VHF DAB/DAB + digital broadcasting networks construction due in the presence of ionospheric propagation of radio waves. These features are considered in this article. Method for calculating the synchronism zone is proposed. Consideration of possible scenarios for the placement of transmitters showed that the most advantageous can be considered their placement at an angle of 90 degrees. Tests of single frequency DRM radio network in the SW range with original methodology were conducted. Measurement results show that synchronous network gain reached the values up to 6 dB at a wire antenna and up to 11 dB at a whip antenna. When using traditional for broadcasting “day” and “night” frequencies it is possible to provide broadcast quality with high reliability (i.e., 98% audio decoding) within 24 hours.