Astra Digital Radio on the early Astra satellites
The analogue switch-off of the Astra 19.2ºE satellites from April 30, 2012, entailed the closure of the Astra Digital Radio service.
ADR was established in 1995 in the activities of the 40th IFA Berlin (August 26-September 3). This system enables the transmission of a digital radio station in stereo on a subcarrier of an analog satellite transponder. This is achieved with a compression of the audio data using Musicam (MPEG 1, Layer II, better known as MP2). The data rate is always 192 kbit/s at 48 kHz (and 9.6 kbps for data).
To receive ADR, special receivers not compatible with the digital broadcasting standard DVB-S are required.
ADR was introduced in Germany for direct satellite reception as opposed to Digital Satellitenradio (DSR), which until 1999 and since the 80s used an entire transponder to transmit 16 radio stations in PCM. Although DSR was better due to the quality of uncompressed sound transmission, the large number of existing radio stations in Germany made mass distribution of these impossible through the system. Hence, it has only been possible to achieve through DVB-S.
In addition to the direct reception of ADR, it is also used to facilitate the feeding of the signal to the transmitting stations and cable headends. Many of the functions of the ADR have only been used by the stations. For example, the ability to show the title of the song and the artist was initially used by very few stations.
In January 2012 the service counted 46 stations in operation with almost all ADR stations already part of the Astra offer in DVB-S format.
ADR system transmitters:
Bayern 1 (BR)
Bayern 2 München (BR)
Bayern 3 (BR)
BR Klassik (BR)
B5 plus (BR)
You FM (hr)
NDR Info Spezial
Antenne Brandenburg Potsdam (rbb)
Radio Eins Potsdam (rbb)
Radio Berlin 88.8 (rbb)
Bremen Vier (Bremen Radio)
SWR4 Baden-Württemberg Stuttgart
SWR4 Rheinland-Pfalz Mainz
SWRinfo (bis 8.Januar 2012 SWR cont.ra)
WDR 2 Rheinland
WDR 4 Rheinland und Bergisches Land
Funkhaus Europa (WDR, Radio Bremen, rbb)