The SIRIUS 4 communications satellite is now in operation and has taken over all transmissions from SIRIUS 2 and 3. Since it was launched on 18 November 2007, all operations have been carried out according to plan.
SIRIUS 4 has now been installed at its final position, 4.8 degrees east. At the same time all channels from its sister satellites, SIRIUS 2 and 3, have been transferred to the new satellite. SIRIUS 4 is intended to meet the increased demand for HDTV broadcasts in the Nordic countries, and the needs arising from the large increase in new television channels within Eastern Europe.
SIRIUS 4 allows the commercialisation of 46 Ku band transponders in the Nordic region, the Baltic States, Central and Eastern Europe. This represents an increase of seven transponders for these regions after the switch from SIRIUS 2 and SIRIUS 3 to SIRIUS 4. Moreover the new satellite will make available another six additional transponders for the African market as well as Ka band capacity for interactive services in the Nordic and Baltic countries.
SIRIUS 4 is a multi-mission Ku/Ka-band satellite. It is built on Lockheed Martin's reliable A2100AX platform. It was successfully launched on November 18, 2007 and is now located at orbital position 5 degrees East.
The satellite will meet today's growing demands for HDTV capacity and tomorrow's new challenges.
SIRIUS 4 has an excellent coverage of the Nordic countries and Eastern Europe. Its lifetime is expected to be minimum 15 years. SIRIUS 4 will be used for direct-to-home transmissions and video and data communication services. SIRIUS 4 has two high power beams (BSS), each equipped with 20 transponders, used for transmission of TV channels to homes with parabolic antennas. One of the beams transmits to the Nordic and Baltic countries (Nordic beam) and the other towards Central and Eastern Europe.
The Nordic beam has a signal power (EIRP) exceeding 52 dBW for all Nordic and Baltic countries. Antennas with a diameter of 60 cm is enough to receive the signal. The footprint of the European beam is larger than for the Nordic beam, but the signal power is still high - at least 50 dBW throughout Central and Eastern Europe. The receiving antenna size required is 60-70 cm. For Western Europe the required antenna diameter would be 60-100 cm.
SIRIUS 4 has three medium power beams (FSS), for video and data communications. One for the Nordic and one for the European area with a total of six 72 MHz transponders. The third beam covers parts of Africa and carries six 36 MHz transponders. The signal power is 48-51 dBW. The uplink band is 14.0-14.25 GHz and the sensitivity is high, thus permitting the use of small uplink antennas.
SIRIUS 4 also carries a dedicated payload for services in the Ka-band (18-30 GHz). Two transponders will enable new types of applications and give new opportunities for e.g. interactive services and contribution.
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