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At least 37 records · Page 2

A portable X-band front-end test package for beam-waveguide antenna performance evaluation. Part 2: Tests on the antenna

Results are given for an X-band (8.45 GHz) test package for testing the new 34-m beam-waveguide antenna at Goldstone in an 'on-the-antenna' configuration. Included are X-band zenith noise temperature values and tipping-curve data obtained at the Cassegrain focal point F1 as well as at the pedestal room focal point F3. Subreflector Z-defocus test results for both F1 and F3 are also presented. The X-band test package operated well in all of the different test configurations and exceeded expected performance.

Otoshi, T. Y.↗

Design and performance analysis of the DSS-13 beam waveguide antenna

A new 34 m research and development antenna is currently being constructed prior to introducing beam waveguide (BWG) antennas and Ka-band (32 GHz) frequencies into the NASA/JPL Deep Space Network. The new 34 m antenna, fed with either a center or bypass BWG, will lose less than 0.2 dB (excluding surface root mean square and mirror misalignment losses), as compared with a standard-fed Cassegrain antenna a X- (8.4 GHz) and Ka-bands. The antenna is currently under construction and is scheduled to be completed July 1990. Phase 1 of the project is for independent X- and Ka-band receive-only tests. Phase 2 of the project is for simultaneous S- (2.3 GHz) and X-band or X- and Ka-band operation, and the design is currently under way.

Veruttipong, T.↗

Environmental Projects: Biological Assessment, Opinion, and New 34-Meter Beam-Waveguide Antenna (DSS 24) at Apollo Site - Volume 17

This report deals with the Biological Assessment, Biological Opinion and Final Report on the construction of a high- efficiency 34-meter, multifrequency beam-waveguide antenna at the Apollo Site of the Goldstone Deep Space Communications Complex, operated by JPL. According to the Endangered Species Act of 1973, a Biological Assessment must be conducted and a Biological Opinion, with terms and conditions, rendered (the Opinion by the U.S. Department of the Interior) before construction of any federal project that may affect endangered or threatened flora or fauna. After construction, a final report is filed with the Department. The desert tortoise, designated "threatened" by the U.S. Fish and Wildlife Service, and the Mojave ground squirrel and the Lane Mountain milk vetch, both designated "candidate threatened," required the reporting specified by the Act. The Assessment found no significant danger to the animal species if workers are educated about them. No stands of the plant species were observed in the surveyed construction area. The Department issued a Biological Opinion to safeguard the two animal species. The Service and the California Department of Fish and Game both issued a Biological Concurrence that JPL had satisfied all environmental criteria for preserving threatened species.

Bengelsdorf, Irving↗

A New Technique for Vernier Pointing of a Beam-Waveguide Antenna

This paper presents a new and simple approach for the Ka-band vernier pointing of a 34m beam-waveguide (BWG) antenna (also applicable to a 70m antenna. In this study, rotation of a BWG flat mirror, located at the elevation axis, is used to scan the beam instead of using the very large tipping structure of the antenna.

antenna pointing vernier pointing beam-waveguide K↗

Optimizing the G/T ratio of the DSS-13 34-meter beam-waveguide antenna

Calculations using Physical Optics computer software were done to optimize the gain-to-noise-temperature (G/T) ratio of Deep Space Station (DSS)-13, the Deep Space Network's (DSN's) 34-m beam-waveguide antenna, at X-band for operation with the ultra-low-noise amplifier maser system. A better G/T value was obtained by using a 24.2-dB far-field-gain smooth-wall dual-mode horn than by using the standard X-band 22.5-dB-gain corrugated horn.

Esquivel, M. S.↗

Atmospheric refraction correction for Ka-band blind pointing on the DSS-13 beam waveguide antenna

An analysis of the atmospheric refraction corrections at the DSS-13 34-m diameter beam waveguide (BWG) antenna for the period Jul. - Dec. 1990 is presented. The current Deep Space Network (DSN) atmospheric refraction model and its sensitivity with respect to sensor accuracy are reviewed. Refraction corrections based on actual atmospheric parameters are compared with the DSS-13 station default corrections for the six-month period. Average blind-pointing improvement during the worst month would have amounted to 5 mdeg at 10 deg elevation using actual surface weather values. This would have resulted in an average gain improvement of 1.1 dB.

Perez-Borroto, I. M.↗

Performance of the X-/Ka/KABLE-band dichroic plate in the DSS-13 beam waveguide antenna

The first Ka-band downlink demonstration was recently carried out by the Ka-Band Link Experiment (KABLE) in association with the Mars Observer spacecraft. In order to support the mission, a dichroic plate was required in the DSS-13 beam waveguide antenna to allow simultaneous X- and Ka-band operation. An X-/ Ka-/ KABLE-band dichroic plate was designed to transmit Ka-band downlink (31.8-32.3 GHz), Ka-band uplink (34.2-34.7 GHz), and KABLE (33.6-33.8 GHz) frequencies, while reflecting X-band (8.4-8.5 GHz). A computer program was developed for the analysis of a dichroic plate with rectangular apertures by using the mode-matching method. The plate was then fabricated and tested. The reflection, group delay, and noise temperature in the antenna system due to the dichroic plate were measured. The experimental results show good agreement with theoretical prediction.

Chen, J. C.↗

Beam-waveguide antenna servo design issues for tracking low earth-orbiting satellites

Upcoming NASA missions will require tracking of low-orbit satellites. As a consequence, NASA antennas will be required to track satellites at higher rates than for the current deep space missions. This article investigates servo design issues for the 34-m beam-waveguide antennas that track low-orbit satellites. This includes upgrading the servo with a feedforward loop, using a monopulse controller design, and reducing tracking errors through either proper choice of elevation pinion location, application of a notch filter, or adjustment of the elevation drive amplifier gain. Finally, improvement of the signal-to-noise ratio through averaging of the over-sampled monopulse signal is described.

Gawronski, W. K.↗

DSS-13 beam waveguide antenna frequency stability

Measurements made on the frequency stability of the DSS-13 34-m diameter Beam Waveguide (BWG) antenna showed that at 46.5 and 37 deg elevation angles, the BWG antenna stability at 12.2 GHz was between 1.3 and 2.2 x 10(exp -15) for tau = 1024 sec and good weather conditions. These frequency stability values apply to the portion of the antenna that includes the main reflector, subreflector, tripod legs, and the six BWG mirrors. The test results reported are believed to be the first known successful measurements of the stability of the microwave optics portion of a large antenna to a level of 1 or 2 parts in 10(exp 15).

Otoshi, T. Y.↗

Portable microwave test packages for beam-waveguide antenna performance evaluations

Portable microwave test packages used to evaluate a new 34-m-diameter beam-waveguide (BWG) antenna are described. The experimental methodology involved transporting test packages to different focal points of the BWG system and making noise temperature, antenna efficiency, and holography measurements. Comparisons of data measured at the different focal points enabled determinations of performance degradations caused by various mirrors in the BWG system. It is shown that, due to remarkable stabilities and accuracies of radiometric data obtained through the use of the microwave test packages, degradations caused by the BWG system were successfully determined.

Otoshi, Tom Y.↗

A portable Ka-band front-end test package for beam-waveguide antenna performance evaluation. Part 1: Design and ground tests

A unique experimental method was used to test the beam waveguide (BWG) antenna at Deep Space Station (DDS) 13 in the Goldstone Deep Space Communications Complex near Barstow, California. The methodology involved the use of portable test packages to make measurements of operating noise temperatures and antenna efficiencies (as functions of antenna pointing angles) at the Cassegrain focal point and the final focal point located in a subterranean pedestal room. Degradations caused by the BWG mirror systems were determined by making comparisons of the measured parameters at the two focal points of the antenna. Previous articles were concerned with the design, performance characteristics, and test results obtained with an X-band test package operating at 32 GHz. Noise temperature measurement results are presented for the Ka-band test package in an on-the-ground test configuration.

Otoshi, T. Y.↗

HRMS sky survey wideband feed system design for DSS 24 beam waveguide antenna

The High-Resolution Microwave Survey (HRMS) Sky Survey project will be implemented on the DSS 24 beam waveguide (BWG) antenna over the frequency range of 2.86 to 10 GHz. Two wideband, ring-loaded, corrugated feed horns were designed to cover this range. The horns match the frequency-dependent gain requirements for the DSS 24 BWG system. The performance of the feed horns and the calculated system performance of DSS 24 are presented.

Stanton, P. H.↗

Strut Shaping of 34m Beam Waveguide Antenna for Reductions in Near-Field RF and Noise Temperature

Strut shaping of NASA's Deep Space Network (DSN) 34m Beam Waveguide (BWG) antenna has been implemented to reduce near-field RF exposure while improving the antenna noise temperature. Strut shaping was achieved by introducing an RF shield that does not compromise the structural integrity of the existing antenna. Reduction in the RF near-field level will compensate for the planned transmit power increase of the antenna from 20 kW to 80 kW while satisfying safety requirements for RF exposure. Measured antenna noise temperature was also improved by as much as 1.5 K for the low elevation angles and 0.5 K in other areas.

near-field↗

The efficiency calibration of the DSS-24 34-meter beam-waveguide antenna

Microwave performance testing of the new Deep Space Station (DSS)-24 34-m-diameter antenna was carried out during the summer of 1994. Efficiency measurements were made at the 8.45 GHz (X-band) and 32-GHz (ka-band) frequencies both at the antenna Cassegrian (f1) and beam-waveguide (f3) focal points. In addition, the antenna f3 efficiencies were measured on the DSS-24 operational 2.295-GHz (S-band) and 8.45-Ghz feeds. This article presents the efficiency determinations as a function of elevation angle along with a corresponding error analysis of the measurements. Peak measured gains and efficiencies are tabulated for all frequencies.

Alvarez, L. S.↗

Noise Temperature Contribution of a Dichroic Plate in a Beam-Waveguide Antenna System

A 34m diameter antenna, built for NASA/JPL in 1990 at Goldstone, California, utilizes a beam-waveguide (BWG) design. It was discovered that if a dichroic plate is installed in a BWG antenna environment, high noise temperatures can result if the receiver system passband is greater than the passband for which the plate was designed. A method is presented for accurately calculating dichroic plate noise temperature for these conditions.

Dichroic Plate Beam-Waveguide Antenna↗

Strut Shaping of 34m Beam Waveguide Antenna for Reductions in Near-Field RF and Noise Temeperature

Struts shaping of the NASA's Deep Space Network (DSN) 34m Beam Waveguide (BWG) antenna has been implemented to reduce near-field RF exposure while improving the antenna noise temperature. Strut shaping was achieved by introducing an RF shield that does not compromise the structural integrity of the existing structure. Reduction in the RF near-field exposure will compensate for the planned transmit power increase of the antenna from 20 kW to 80 kW while satisfying safety requirements for RF exposure. Antenna noise temperature was also improved by as much as 1.5 K for the low elevation angles and 0.5 K in other areas. Both reductions of RF near-field exposure and antenna noise temperature were verified through measurements and agree very well with calculated results.

reflector↗