Showing papers on "L band published in 1989"
TL;DR: Field tests related to planned mobile satellite systems (MSS) were performed, and results that add to the existing database of propagation measurements at L-band (1.5 GHz) are described.
Abstract: Field tests related to planned mobile satellite systems (MSS) were performed, and results that add to the existing database of propagation measurements at L-band (1.5 GHz) are described. They are considered particularly useful in that propagation effects were studied systematically with repeated and controlled runs pertaining to different path elevation angles, road types, and path geometries defining shadowing and line-of-sight modes. In addition, simultaneous L-band and UHF measurements were performed for the purpose of establishing scaling factors applicable to previous UHF (870 MHz) results. The control of the experimental parameters was made possible by using a helicopter as the source platform and a mobile van which housed the receiver. >
94 citations
13 Jun 1989
TL;DR: In this article, a four-channel, contiguous-band output multiplexer for L-band satellite applications is described, which can operate at power levels up to 13 W in vacuum.
Abstract: A four-channel, contiguous-band output multiplexer for L-band satellite applications is described. The filters feature single- and dual-mode dielectric resonators and operate at power levels up to 13 W in vacuum. The design of the multiplexer was optimized to meet different requirements for each of the filters. Excellent electrical performance in a relatively small package was obtained by use of high-performance dielectric resonators and a coaxial line combiner. >
8 citations
15 Aug 1989
TL;DR: In this article, satellite propagation measurements from both the Japanese ETS-5 and INMARSAT Pacific geostationary satellites were accessed during an 11-day period in South-Eastern Australia.
Abstract: Land-mobile satellite propagation measurements were implemented at L Band (1.5 GHz) in South-Eastern Australia during an 11 day period in October 1988. Transmissions (CW) from both the Japanese ETS-5 and INMARSAT Pacific geostationary satellites were accessed. Previous measurements in this series were performed at both L Band (1.5 GHz) and UHF (870 MHz) in Central Maryland, North-Central Colorado, and the southern United States. The objectives of the Australian campaign were to expand the data base acquired in the U.S. to another continent, to validate a U.S. derived empirical model for estimating the fade distribution, to establish the effects of directive antennas, to assess the isolation between co- and cross-polarized transmissions, to derive estimates of fade as well as non-fade durations, and to evaluate diversity reception. All these objectives were met.
4 citations
15 Feb 1989
TL;DR: In this article, the calibration of the 70-meter antenna at C-band (5.01 GHz) and L-band(1.668 GHz) is described, and the test procedure is described including block diagrams, and results are presented for efficiency, system temperature, and pointing.
Abstract: The calibration of the 70-meter antenna at C-band (5.01 GHz) and L-band (1.668 GHz) is described. This calibration comes after a modification to an existing L-band feed to include the C-band frequencies. The test technique employs noise-adding radiometers and associated equipment running simultaneously at both frequencies. The test procedure is described including block diagrams, and results are presented for efficiency, system temperature, and pointing.
2 citations