DRM (Digital Radio Mondiale) Local Coverage Tests Using the 26 MHz Broadcasting Band

The digital sound broadcasting DRM (Digital Radio Mondiale) standard has established worldwide, and the number of transmissions on air has increased significantly since the approval of the standard. This paper presents the results of the one of the first DRM field trials using the 26 MHz band for local broadcasting that were carried out in Mexico. The main objective of these trials was to test the usage of the 26 MHz frequency broadcasting band to cover a local area in a similar way to FM broadcasting. This band has been usually used to broadcast long distance transmissions mainly under high sun-spot activity. When the 26 MHz band is used for local broadcasting, the tropospheric propagation is the main mechanism instead of the ionospheric refraction used in HF. At these frequencies the first Fresnel ellipsoid is usually obstructed, and multipath at urban environments is strong. In this article, practical minimum signal-to-noise ratio and field strength levels are calculated for this novel usage of the 26 MHz frequency band