ISBN: | 978-5-5125-5621-4 |
High Quality Content by WIKIPEDIA articles! Astra Digital Radio (ADR) is a system used by SES Astra for digital radio transmissions on their Astra 1 satellites, using the audio subcarrier frequencies of analogue television channels. It was introduced in 1995. As of February 2008, there are still 51 stations transmitting in this format.