Satellite television C. Clarke proposed a worldwide communications system which would function by means of three satellites equally spaced apart in earth orbit. This was published in the October 1945 issue of the Wireless World magazine and won him the Franklin Institute's Stuart Ballantine Medal in 1963. The first public satellite television signals from Europe to North America were relayed via the Telstar satellite over the Atlantic ocean on 23 July 1962, although a test broadcast had taken place almost two weeks earlier on 11 July. The signals were received and broadcast in North American and European countries and watched by over
Satellite data unit Satellite data unit A satellite data unit (SDU) is an avionics device installed in an aircraft that allows air/ground communication via a satellite network. It is an integral part of an aircraft's SATCOM (satellite communication) system. The device connects with a satellite via ordinary radio frequency (RF) communication and the satellite then connects to a ground station or "vice versa". All satellite communication whether audio or data is processed by the SDU. The SDU communicates with an onboard MDDU (multi-purpose disk-drive unit) which maintains an updatable table of ground stations in the aircraft's current area and the order of preference