Appendix C: A look into the world’s first SDR, and it’s successors

(Appendix to page ‘Filling the space that Worldspace has left… at least to some extend’)

No doubt, the world’s first L-band/S-band satellite radio was the Worldspace. But the worlds first satellite radio was the Digitales Satelliten Radio (DSR) service, which was in operation in Germany from 1989 to 1999, broadcasting 16 radio channels of truly CD quality music to be directly picked up by a rooftop antenna (which was either today’s DTH styled ‘bowl’ dish, or “a small flat antenna with an edge length of only 30 cm” also fixed on rooftop), and a special DSR receiver. Like the concept DTH Radio described in this write up, both DSR was meant for fixed home reception.

Astra Digital Radio (ADR) started in the mid 90’s in Germany (unrelated to Astro Radio that was referred to in the main article), and soon replaced DSR when the latter was discontinued. ADR, like today’s DTVr services, utilized the TV broadcast satellites to broadcast radio channels, transferring digital radio programs – providing about 50 radio channels – in stereo via subcarriers of analog satellite television programs

Similar to ADR was the method of transmitting radio as analog satellite audio through channels where video would normally be transmitted on a satellite transponder. The method was known as or FM-Squared (written as FM², FM(2) or simply as FM/FM), developed in 1986 by Wegener Communications and Subcarrier Systems (later SpaceCom Systems, Inc.) which was once used to distribute Muzak and similar "business" music (that played in the ambience of hotel lobbies, restaurants and elevators, and therefore also referred to as elevator music) to retailers, but widely used to transmit radio, to be picked up by hobbyists using receivers like Universal SC-50 “Audio Subcarrier / FM(2) Satellite Receiver”