Open Access

Thomas Lauterbach

• Using DRM in the 26 MHz band is an interesting option for local braodcasting. A field trial was set up with two low power DRM transmitters in the area of Nuremberg. Mobile reception was found to be possible at distances of up to 20 km to the transmitter. However, audio dropouts due to flat fading in the multipath channel were frequently observed at low vehicle speed. Fixed reception with outdoor antennas was found to be possible at distances of more than 40 km. An overall availability of the audio signal of 99.2 % was achieved at seven different locations during ten days. Long term recordings of several hundreds of hours at one location showed that audio availability was better than 97% in many cases but was reduced at times by local sources of noise and interfering signals from distant stations when ionospheric scattering was possible due to high solar activity and sporadic E layers. Based on these findings it is concluded that for service planning the same procedures as for VHF transmitter networks can be applied. However to avoidUsing DRM in the 26 MHz band is an interesting option for local braodcasting. A field trial was set up with two low power DRM transmitters in the area of Nuremberg. Mobile reception was found to be possible at distances of up to 20 km to the transmitter. However, audio dropouts due to flat fading in the multipath channel were frequently observed at low vehicle speed. Fixed reception with outdoor antennas was found to be possible at distances of more than 40 km. An overall availability of the audio signal of 99.2 % was achieved at seven different locations during ten days. Long term recordings of several hundreds of hours at one location showed that audio availability was better than 97% in many cases but was reduced at times by local sources of noise and interfering signals from distant stations when ionospheric scattering was possible due to high solar activity and sporadic E layers. Based on these findings it is concluded that for service planning the same procedures as for VHF transmitter networks can be applied. However to avoid interference by ionosperic scattering, cochannel transmitters must be seperated by at least 2500 km. Therefore, only one channel will be available in each place.…