Sound broadcasting applications of highly elliptical orbits

Through two contracts placed with Aerospatiale and British Aerospace, the European Space Agency has studied in detail the application of highly elliptical orbits to mobile communications in Europe. Through this work it has become clear that despite the relatively `unconventional´ nature of these orbits, their use has a number of advantages, mainly related to avoidance of shadowing and the possibility of increasing the gain of the mobile antenna. Whilst relatively high user numbers would be involved in mobile communications, it was recognised that in the parallel area of satellite broadcasting there would be a huge expansion of the mobile user population with all the advantages of shadowing avoidance and mobile G/T enhancement. As a consequence additional work was commissioned from the two main contractors in order to consider the problems of satellite sound broadcasting specifically. Apart from the recent work of the Agency, the EBU has, through its specialist group structure, been considering the implications of digital radio broadcasting systems at frequencies around 1.5 GHz for fixed and mobile reception