INTELSAT propagation experiments: the focus and results of recent campaigns

Article Abstract:

Frequency reuse is used in INTELSAT satellites to meet increasing capacity requirements; six- or eight-fold frequency reuse may be required in both C- and Ku-bands in INTELSAT spacecraft to be launched in the next century. Propagation measurements were made prior to use of new frequency band or reuse techniques to quantify likely impairment levels. Depolarization was found to be the limiting propagation impairment at C-band, but rain attenuation was usually insignificant. Rain depolarization was not a system-limiting impairment at Ku-band for elevation angles above about 10o. New service opportunities make necessary a greater understanding of the propagation requirements in new climatic zones and under different system configurations. They have been categorized at INTELSAT into four groups: low latitudes, western Pacific rim, VSAT operations, and impairment countermeasures.

Product introduction, Meteorology, Measurement, New Technique, Expansion, Frequency

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Results from 12- to 30-GHz German propagation experiments carried out with radiometers and the OLYMPUS satellite

Article Abstract:

The Telekom's Research Centre at Darmstadt, Germany, is participating in the OLYMPUS propagation experiments at Ka and Ku-band frequencies; the activities are in association with the OLYMPUS Propagation Experimenters Group (OPEX), which conducted propagation measurements with the OLYMPUS satellite at 12.5, 20, and 30 GHz in Europe and the US. The center had previously conducted 30-GHz measurements as part of the European ATS-6 campaign and with the SIRIO and OTS satellites in the 12-GHz band. Also made were long-term 30-GHz site diversity studies using three radiometers in an isosceles and rectangular configuration with site separations of about 18 km and 26 km, respectively. The study was intended to improve assessment of the potential for high-quality satellite services in this band; the measurement programs are reviewed, and some of the relevant results are presented.

Europe, Industrial research, Telecommunications, Bandwidth, Research and Development, Communications Technology, Performance Prediction, Bandwidth Technology

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Radio propagation experiments in the outer solar system with Voyager

Article Abstract:

Two Voyager spacecraft transmitted microwave telecommunications from Jupiter, Saturn, and Uranus. The signals enable researchers on Earth to study the planets' atmospheres, ionospheres, rings, and magnetic fields. The signals provide accurate images to within a few tens of meters. The signals also measure atmospheric irregularities at the outer planets. Researchers can also study the slant and strength of the planets magnetic fields. Improvements in the transmitters of future spacecraft would improve the range and sensitivity of these measurements.

Magnetic fields, Space Craft, Radio Communication, Microwave Communication

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