The New Wuqing 70 m Radio Telescope and Measurements of Main Electronic Properties in X-band

2022 ◽  
Author(s):  
De-Qing Kong ◽  
Chunlai Li ◽  
Hongbo Zhang ◽  
Yan Su ◽  
Jian-Jun Liu ◽  
...  
Keyword(s):  
Flux Density ◽  
Radio Telescope ◽  
Noise Temperature ◽  
Calibration Model ◽  
Space Communications ◽  
Condi Tions ◽  
X Band ◽  
Measurement Results ◽  
Pointing Accuracy ◽  
Exploration Mission

Abstract The new Wuqing 70 m radio telescope is firstly used for the downlink data reception in the first Mars exploration mission of China, and will be used for the other deep space communications and radio astronomical observations in the future. The main specifications and measurement results of some properties in X-band are introduced in this paper, such as pointing calibration, gain and efficiency, system noise temperature, system equivalent flux density, and variations with elevation. The 23 parameters pointing calibration model considering the atmospheric refraction correction in real time is presented in the telescope, and the pointing accuracy is reached 5.70″ in azimuth direction and 6.07″ in elevation direction respectively for different weather condi-tions. More than 62% efficiencies are achieved at full elevation range, and more than 70% in the mid-elevation. The system equivalent flux density of X-band in the mid-elevation is reached 26 Jy.

scholarly journals Performance Evaluation of Irbene RT-16 Radio Telescope Receiving System

2017 ◽  
Vol 54 (6) ◽  
pp. 42-53 ◽  
Author(s):  
M. Bleiders ◽  
Vl. Bezrukovs ◽  
A. Orbidans
Keyword(s):  
Performance Evaluation ◽  
Flux Density ◽  
Radio Telescope ◽  
Total Power ◽  
Recent Measurement ◽  
Future Performance ◽  
Cassegrain Antenna ◽  
Vlbi Observations ◽  
Measurement Results ◽  
Beam Patterns

Abstract In the present paper, recent measurement results of refurbished Irbene RT-16 radio telescope receiving system performance are presented. The aim of the research is to evaluate characteristics of RT-16, which will allow carrying out necessary amplitude calibration in both single dish and VLBI observations, to improve the performance of existing system as well as to monitor, control and compare performance if possible changes in the receiving system will occur in future. The evaluated receiving system is 16 m Cassegrain antenna equipped with a cryogenic receiver with frequency range from 4.5 to 8.8 GHz, which is divided into four sub-bands. Multiple calibration sessions have been carried out by observing stable astronomical sources with known flux density by using in-house made total power registration backend. First, pointing offset calibration has been carried out and pointing model coefficients calculated and applied. Then, amplitude calibration, namely antenna sensitivity, calibration diode equivalent flux density and gain curve measurements have been carried out by observing calibration sources at different antenna elevations at each of the receiver sub-bands. Beam patterns have also been evaluated at different frequency bands. As a whole, acquired data will serve as a reference point for comparison in future performance evaluation of RT-16.

scholarly journals The Sgr B2 Region Seen at 43 GHZ

1987 ◽  
Vol 115 ◽  
pp. 158-160
Author(s):  
Hisashi Hirabayashi ◽  
Kenji Akabane ◽  
Masaki Morimoto ◽  
Yosiaki Sofue ◽  
Makato Inoue ◽  
...  
Keyword(s):  
Flux Density ◽  
Noise Temperature ◽  
Central Frequency ◽  
Radio Observatory ◽  
System Noise ◽  
Ngc 7027 ◽  
Pointing Accuracy ◽  
Half Power ◽  
5 Ghz ◽  
Better Than

The Sgr B2 region was mapped at 43 GHz (λ = 6.9 mm) with the 45m radio telescope of Nobeyama Radio Observatory. The observing parameters were: a) half power beamwidth 38″, b) pointing accuracy better than 10″, c) central frequency 43.0 GHz, d) bandwidth 500 MHz, and e) system noise temperature 400 K; and the observational aspects were: a) mapping with one polarization, b) liquid-nitrogen cooled load switching and c) reduction by NOD-2 programme. The obtained map is shown in Figure 1. Sgr B2 is resolved into several components which correspond to those by Martin and Downes (1972) and Downes et al. (1978). But the component at RA = 17h44m11.8s Dec. = −28°23′55″ at 1950 is not seen in Martin and Downes (1972) nor in the 5 GHz map of Downes et al. (1978), although the feature is seen in the 10.7 GHz map of Downes et al. (1978). The components derived from the map in Figure 1 by a morphological estimate are listed in Table 1. The total flux density of the region is 146J±30 Jy. The intensity calibration was made by observing NGC 7027.

scholarly journals Multi-Probe Measurement System Based on Single-Cut Transformation for Fast Testing of Linear Arrays

Sensors ◽  
2021 ◽  
Vol 21 (5) ◽  
pp. 1744
Author(s):  
Fernando Rodríguez Varela ◽  
Manuel José López Morales ◽  
Rubén Tena Sánchez ◽  
Alfonso Tomás Muriel Barrado ◽  
Elena de la Fuente González ◽  
...  
Keyword(s):  
Measurement System ◽  
Near Field ◽  
Linear Measurement ◽  
Complete Characterization ◽  
Linear Arrays ◽  
Full Characterization ◽  
X Band ◽  
Measurement Results ◽  
The Many ◽  
3D Information

This paper introduces a near-field measurement system concept for the fast testing of linear arrays suited for mass production scenarios where a high number of nominally identical antennas needs to be measured. The proposed system can compute the radiation pattern, directivity and gain on the array plane, as well as the array complex feeding coefficients in a matter of seconds. The concept is based on a multi-probe antenna array arranged in a line which measures the near field of the antenna under test in its array plane. This linear measurement is postprocessed with state-of-the-art single-cut transformation techniques. To compensate the lack of full 3D information, a previous complete characterization of a “Gold Antenna” is performed. This antenna is nominally identical to the many ones that will be measured with the proposed system. Therefore, the data extracted from this full characterization can be used to complement the postprocessing steps of the single-cut measurements. An X-band 16-probe demonstrator of the proposed system is implemented and introduced in this paper, explaining all the details of its architecture and operation steps. Finally, some measurement results are given to compare the developed demonstrator with traditional anechoic measurements, and show the potential capabilities of the proposed concept to perform fast and reliable measurements.

HYGIENIC ASSESSMENT OF ELECTROMAGNETIC RADIATION LEVELS OF BASE STATIONS,INSTALLED ON THE ROOFS OF BUILDINGS AND THE TERRITORY OF LAND PLOTS IN TASHKENT

2021 ◽  
Vol 2 (5) ◽  
pp. 5-11
Author(s):  
G. A. Tashpulatova ◽  
◽  
A. N. Krasavin
Keyword(s):  
Public Health ◽  
Electromagnetic Radiation ◽  
Flux Density ◽  
Energy Flux ◽  
Mobile Communications ◽  
Base Station ◽  
Base Stations ◽  
Cellular Communications ◽  
Measurement Results ◽  
Energy Flux Density

This article is about instrumental measurements of the FR EMR energy flux density. The measurement results were analyzed with the division of the data obtained by the purpose of buildings and the height of the antenna equipment placement, a hygienic assessment of the RF EMR levels created by the equipment of base stations of cellular communications, installed on the roofs of residential and public buildings and adjacent territories of Tashkent is given. A proposal is made on the rational placement of radio engineering facilities.Keywords:electromagnetic field; electromagnetic safety; base station for mobile communications; protection of public health; sanitary supervision

scholarly journals Radio light-curve for WR 146 (HM19-3, WC6+O8.5), a colliding wind binary

1999 ◽  
Vol 193 ◽  
pp. 390-391
Author(s):  
Diah Y.A. Setia Gunawan ◽  
A. Ger de Bruyn ◽  
Karel A. van der Hucht ◽  
Peredur M. Williams
Keyword(s):  
Light Curve ◽  
Flux Density ◽  
Radio Telescope ◽  
Time Scale ◽  
Preliminary Results ◽  
Average Flux

We report preliminary results of monitoring the flux from the Wolf-Rayet object WR 146 with the Westerbork Synthesis Radio Telescope at 21 cm since 1989. We find the average flux density slowly rising in the period 1989–1997, with evidence of shorter time-scale variability.

scholarly journals Compact Differential-Fed Planar Filtering Antennas

Electronics ◽  
2019 ◽  
Vol 8 (11) ◽  
pp. 1241
Author(s):  
Emadeldeen Hassan ◽  
Denys Martynenko ◽  
Eddie Wadbro ◽  
Gunter Fischer ◽  
Martin Berggren
Keyword(s):  
Frequency Band ◽  
Optimization Problem ◽  
Impedance Bandwidth ◽  
Cross Polarization ◽  
Planar Antennas ◽  
Good Match ◽  
Topology Optimization Problem ◽  
Low Profile ◽  
X Band ◽  
Measurement Results

This paper proposes novel low-profile differential-fed planar antennas with embedded sharp frequency selectively. The antennas are compact and easy to integrate with differential devices without matching baluns. The antenna design is formulated as a topology optimization problem, where requirements on impedance bandwidth, directivity, and filtering are used as the design objectives. The optimized antennas operate over the frequency band 6.0–8.5 GHz. The antennas have reflection coefficients below −15 dB, cross-polarization levels below −42 dB, a maximum gain of 6.0 ± 0.5 dB, and a uniform directivity over more than 130° beamwidth angle in the frequency band of interest. In addition, the antennas exhibit sharp roll-off between the operational band and frequencies around the 5.8 GHz WiFi band and the 10 GHz X-band. One antenna has been fabricated with a good match between simulation and measurement results.

scholarly journals Statistics of the 6.7 GHz methanol maser variability from the Toruń survey

2002 ◽  
Vol 206 ◽  
pp. 135-138
Author(s):  
Anna Niezurawska ◽  
Marian Szymczak ◽  
Grzegorz Hrynek ◽  
Andrzej J. Kus
Keyword(s):  
Flux Density ◽  
Time Scales ◽  
Radio Telescope ◽  
Methanol Maser ◽  
Maser Line

A sample of 174 methanol sources has been observed with the 32 m Toruń radio telescope at four or five epochs separated by 3-7 months. Observations of the 6.7 GHz maser line revealed that about 80% of sources are variable. 20% of sources showed strong variations of the integrated flux density usually on time-scales of 5-12 months. These variations were associated with strong changes in the relative intensities of maser features. Methanol emission from five sources disappeared. The time-scales of variability were longer than 12 months for only 23% of variable sources. It is suggested that the variability of methanol emission is related to the dynamics of the maser regions.

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