The Advanced Communications Technology Satellite Propagation Studies Workshop (APSW) is convened ... more The Advanced Communications Technology Satellite Propagation Studies Workshop (APSW) is convened each year to present the results of the Advanced Communications Technology Satellite (ACTS) Ka-band propagation campaign. Representatives from the space ...
GHz " (JPL task plan No. 81-6775). The goal of this study has been to perform an evaluation ... more GHz " (JPL task plan No. 81-6775). The goal of this study has been to perform an evaluation of radio wave propagation losses at SHF band by using available propagation models and several benchmark scenarios. The Department of Defense is exploring the possibility of occupying the microwave range of 3–30 GHz to increase bandwidth. As frequency increases, crucial changes to link power margins must be examined. Dominantly responsible for additional losses to the free space loss in the transmitted signal are atmospheric absorption, clouds, fog, and precipitation, as well as scintillation/multipath at low elevation angles. All of these losses due to the atmosphere at the studied frequency range cannot be neglected. The free space Friis Equation has been modified to add an additional term, which includes all atmospheric attenuation and fading effects. First, we completed an extensive literature search on SHF band propagation studies. Microwave propagation models from the International...
Abstract. A study of directional discontinuities (DDs) that occurred during 4 days of the Ulysses... more Abstract. A study of directional discontinuities (DDs) that occurred during 4 days of the Ulysses north polar pass was conducted (461 directional discontinuities total) using magnetic field and plasma data. We find that the total number of directional discontinuities selected by the Tsurutani and Smith (1979) method are the same in the north and south polar regions (within statistical errors) if the radial gradient is taken into account. We also find that tangential discontinuities (TDs) occur at edges of mirror mode structures. Approximately half of these structures are locally unstable. TDs are also associated with interplanetary current sheets, some of which are in regions of positive solar wind velocity gradients. To first order, we find no difference in the number of directional discontinuities, number of TDs, or the types of TDs in the north polar region from the south polar region. Key words: interplanetary medium – plasmas 1.
This article introduces a method to estimate the aggregate interference from future highdensity f... more This article introduces a method to estimate the aggregate interference from future highdensity fixed service emitters to deep-space Earth stations. In this method, the area sur rounding the deep-space Earth station is geometrically partitioned, and this partition is used to model the correlation of interferences. The propagation losses are calculated considering the terrain and the atmospheric conditions. The method uses statistical models and their numerical approximations to estimate the aggregate interference. This method is applied to the areas surrounding the deep-space Earth stations of NASA’s Deep Space Network (DSN) at Goldstone–USA, Robledo–Spain, and Tidbinbilla–Australia to estimate the aggregate interference received from any given geographical distribution of high-density fixed service emitters in the 37-GHz band. It also provides a basis to establish emission limits for these emitters to ensure compatibility of operation between the high-density fixed service and the ...
In this study, the fluctuation ranges and mean values of solar brightness temperatures at microwa... more In this study, the fluctuation ranges and mean values of solar brightness temperatures at microwave frequencies are estimated using solar radio emission fluxes at 2800 and 8800 MHz measured through several solar cycles. These variations include both short-term ( ...
Abstract: In this article, most of widely accepted radio wave propagation models that have proven... more Abstract: In this article, most of widely accepted radio wave propagation models that have proven to be accurate in practice as well as numerically efficient at SHF band will be reviewed. Weather and terrain data along the signal's paths can be input in order to more ...
Page 1. Interference from the Robledo DSN Transmitters to Central Madrid IMT-2000lUMTS System thr... more Page 1. Interference from the Robledo DSN Transmitters to Central Madrid IMT-2000lUMTS System through Terrain Diffraction at S-Band Christian M. Ho', Miles K. Sue1, Ted K. ~ eng ' and Ernest K. Smith2 ' ~ et Propulsion ...
ABSTRACT.—The Spectrum Engineering Group conducted a series of terrestrial interference tests at ... more ABSTRACT.—The Spectrum Engineering Group conducted a series of terrestrial interference tests at Goldstone, California, on October 23–25, 2009, using Deep Space Station (DSS)–13 to receive at 32 GHz. The role of interfering emitter was played by a 1-W ...
A large number of microwave transmitters will be installed in large urban centers in the future t... more A large number of microwave transmitters will be installed in large urban centers in the future to provide high-density fixed services (HDFS). The frequency band proposed for use by these transmitters overlaps the Ka-band (27–40 GHz) allocated for NASA's Deep ...
Journal of Geophysical Research: Space Physics, 1997
The Jovian magnetopause boundary layer (BL) plasma wave spectra from 10−3 to 102 Hz have been mea... more The Jovian magnetopause boundary layer (BL) plasma wave spectra from 10−3 to 102 Hz have been measured for the first time. For one intense event the magnetic (B′) and electric (E′) spectra were 2 × 10−4 ƒ2.4 nT2/Hz and 4 × 10−9 ƒ2.4 V2/m2 Hz, respectively. Although no measurable wave amplitudes were detected above the electron gyrofrequency, ∼140 Hz, this finding may be due to the low signal strength characteristic of this region. The B′/E′ ratio is relatively frequency independent. It is possible that waves are obliquely propagating whistler mode waves. The B′ and E′ spectra are broadband with no obvious spectral peaks. The waves are sufficiently intense to cause cross‐field diffusion of magnetosheath plasma to create the BL itself. A Jovian BL thickness of 10,700 km is predicted, which is consistent with past in situ measurements. The Jovian boundary layer wave properties are quite similar to the BL waves at Earth (however, the Jovian waves are orders of magnitude less intense). I...
Journal of Geophysical Research: Space Physics, 1996
This paper presents the results of the first statistical study of interplanetary directional disc... more This paper presents the results of the first statistical study of interplanetary directional discontinuities at both low and high heliographic latitudes measured by the Ulysses magnetometer. There is a gradual decrease in the rate of occurrence of interplanetary discontinuities (ROIDs) with increasing radial distance. From 1 to 5 AU, an e−(r−1)/5 dependence is derived. Much of this decrease is believed to be an artifact due to the discontinuity thickening with decreasing |B|, falling outside the detection criteria. As Ulysses goes from the ecliptic plane to high (−80°) heliographic latitudes, the ROID value increases dramatically. The increase is about a factor of 5 as Ulysses moves from Jupiter at 5 AU to 2.5 AU over the south pole. There is a one‐to‐one correspondence between high ROID values and high‐speed streams. This is particularly dramatic just after the Jovian encounter when there are ∼25.4‐day period corotating streams present. Thus the increase with latitude is primarily ...
The Advanced Communications Technology Satellite Propagation Studies Workshop (APSW) is convened ... more The Advanced Communications Technology Satellite Propagation Studies Workshop (APSW) is convened each year to present the results of the Advanced Communications Technology Satellite (ACTS) Ka-band propagation campaign. Representatives from the space ...
GHz " (JPL task plan No. 81-6775). The goal of this study has been to perform an evaluation ... more GHz " (JPL task plan No. 81-6775). The goal of this study has been to perform an evaluation of radio wave propagation losses at SHF band by using available propagation models and several benchmark scenarios. The Department of Defense is exploring the possibility of occupying the microwave range of 3–30 GHz to increase bandwidth. As frequency increases, crucial changes to link power margins must be examined. Dominantly responsible for additional losses to the free space loss in the transmitted signal are atmospheric absorption, clouds, fog, and precipitation, as well as scintillation/multipath at low elevation angles. All of these losses due to the atmosphere at the studied frequency range cannot be neglected. The free space Friis Equation has been modified to add an additional term, which includes all atmospheric attenuation and fading effects. First, we completed an extensive literature search on SHF band propagation studies. Microwave propagation models from the International...
Abstract. A study of directional discontinuities (DDs) that occurred during 4 days of the Ulysses... more Abstract. A study of directional discontinuities (DDs) that occurred during 4 days of the Ulysses north polar pass was conducted (461 directional discontinuities total) using magnetic field and plasma data. We find that the total number of directional discontinuities selected by the Tsurutani and Smith (1979) method are the same in the north and south polar regions (within statistical errors) if the radial gradient is taken into account. We also find that tangential discontinuities (TDs) occur at edges of mirror mode structures. Approximately half of these structures are locally unstable. TDs are also associated with interplanetary current sheets, some of which are in regions of positive solar wind velocity gradients. To first order, we find no difference in the number of directional discontinuities, number of TDs, or the types of TDs in the north polar region from the south polar region. Key words: interplanetary medium – plasmas 1.
This article introduces a method to estimate the aggregate interference from future highdensity f... more This article introduces a method to estimate the aggregate interference from future highdensity fixed service emitters to deep-space Earth stations. In this method, the area sur rounding the deep-space Earth station is geometrically partitioned, and this partition is used to model the correlation of interferences. The propagation losses are calculated considering the terrain and the atmospheric conditions. The method uses statistical models and their numerical approximations to estimate the aggregate interference. This method is applied to the areas surrounding the deep-space Earth stations of NASA’s Deep Space Network (DSN) at Goldstone–USA, Robledo–Spain, and Tidbinbilla–Australia to estimate the aggregate interference received from any given geographical distribution of high-density fixed service emitters in the 37-GHz band. It also provides a basis to establish emission limits for these emitters to ensure compatibility of operation between the high-density fixed service and the ...
In this study, the fluctuation ranges and mean values of solar brightness temperatures at microwa... more In this study, the fluctuation ranges and mean values of solar brightness temperatures at microwave frequencies are estimated using solar radio emission fluxes at 2800 and 8800 MHz measured through several solar cycles. These variations include both short-term ( ...
Abstract: In this article, most of widely accepted radio wave propagation models that have proven... more Abstract: In this article, most of widely accepted radio wave propagation models that have proven to be accurate in practice as well as numerically efficient at SHF band will be reviewed. Weather and terrain data along the signal's paths can be input in order to more ...
Page 1. Interference from the Robledo DSN Transmitters to Central Madrid IMT-2000lUMTS System thr... more Page 1. Interference from the Robledo DSN Transmitters to Central Madrid IMT-2000lUMTS System through Terrain Diffraction at S-Band Christian M. Ho', Miles K. Sue1, Ted K. ~ eng ' and Ernest K. Smith2 ' ~ et Propulsion ...
ABSTRACT.—The Spectrum Engineering Group conducted a series of terrestrial interference tests at ... more ABSTRACT.—The Spectrum Engineering Group conducted a series of terrestrial interference tests at Goldstone, California, on October 23–25, 2009, using Deep Space Station (DSS)–13 to receive at 32 GHz. The role of interfering emitter was played by a 1-W ...
A large number of microwave transmitters will be installed in large urban centers in the future t... more A large number of microwave transmitters will be installed in large urban centers in the future to provide high-density fixed services (HDFS). The frequency band proposed for use by these transmitters overlaps the Ka-band (27–40 GHz) allocated for NASA's Deep ...
Journal of Geophysical Research: Space Physics, 1997
The Jovian magnetopause boundary layer (BL) plasma wave spectra from 10−3 to 102 Hz have been mea... more The Jovian magnetopause boundary layer (BL) plasma wave spectra from 10−3 to 102 Hz have been measured for the first time. For one intense event the magnetic (B′) and electric (E′) spectra were 2 × 10−4 ƒ2.4 nT2/Hz and 4 × 10−9 ƒ2.4 V2/m2 Hz, respectively. Although no measurable wave amplitudes were detected above the electron gyrofrequency, ∼140 Hz, this finding may be due to the low signal strength characteristic of this region. The B′/E′ ratio is relatively frequency independent. It is possible that waves are obliquely propagating whistler mode waves. The B′ and E′ spectra are broadband with no obvious spectral peaks. The waves are sufficiently intense to cause cross‐field diffusion of magnetosheath plasma to create the BL itself. A Jovian BL thickness of 10,700 km is predicted, which is consistent with past in situ measurements. The Jovian boundary layer wave properties are quite similar to the BL waves at Earth (however, the Jovian waves are orders of magnitude less intense). I...
Journal of Geophysical Research: Space Physics, 1996
This paper presents the results of the first statistical study of interplanetary directional disc... more This paper presents the results of the first statistical study of interplanetary directional discontinuities at both low and high heliographic latitudes measured by the Ulysses magnetometer. There is a gradual decrease in the rate of occurrence of interplanetary discontinuities (ROIDs) with increasing radial distance. From 1 to 5 AU, an e−(r−1)/5 dependence is derived. Much of this decrease is believed to be an artifact due to the discontinuity thickening with decreasing |B|, falling outside the detection criteria. As Ulysses goes from the ecliptic plane to high (−80°) heliographic latitudes, the ROID value increases dramatically. The increase is about a factor of 5 as Ulysses moves from Jupiter at 5 AU to 2.5 AU over the south pole. There is a one‐to‐one correspondence between high ROID values and high‐speed streams. This is particularly dramatic just after the Jovian encounter when there are ∼25.4‐day period corotating streams present. Thus the increase with latitude is primarily ...
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