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The Compound Astronomical Low-Cost Low-Frequency Instrument for Spectroscopy and Transportable Observatory (CALLISTO) is a worldwide network of radio spectrometers designed for 24-hour solar observation. It is a collaboration among the Swiss Federal Institute of Technology Zurich and numerous local host institutes, spread out around the world. This...
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The occasion of the partial solar eclipse in Malaysia occurred on 9th March 2016 covered almost 67% to 80% of the whole Sun. During the maximum time of the partial solar eclipse, some of the solar emission and sunlight was blocked to reach the Earth's surface. In order to see this effect to a radio signal, the analysis of radio signal pattern befor...
Citations
... The present work is motivated by the scientific and technical accomplishments of various research groups that built and commissioned several solar radio spectrometer and SP instruments in the past across the globe. One may refer to the articles listed here and the references therein to know those groups and their technical contributions: Wild & McCready (1950), Wild et al. (1954), Thompson (1961), Mosier & Fainberg (1975), Kaverin et al. (1979), Dumas et al. (1982), Perrenoud (1982), Jin et al. (1986), Allaart et al. (1990), Benz et al. (1990), Mann et al. (1992), Bogod et al. (1993), Jiricka et al. (1993), Prestage (1995), Sawant et al. (2001), Fu et al. (2004), Kontogeorgos et al. (2006), Ebenezer et al. (2007), Benz et al. (2009aBenz et al. ( , 2009b, Zucca et al. (2012), Antar et al. (2014), Kishore et al. (2014), Kishore et al. (2015), Du et al. (2017), Puricer et al. (2019), and Hamini et al. (2021). In addition to the above, the recently built large radio facilities such as the Long Wavelength Array (Ellingson et al. 2009), the Murchison Widefield Array (Tingay et al. 2013), and the LOw-Frequency ARray (Van Haarlem et al. 2013) have been used to observe the low-frequency radio spectral and spectro-polarimetric signatures of the Sun with high spatial, temporal, and frequency resolution, through proposals. ...
The Zeeman effect has been routinely used to image and quantify the solar photospheric magnetic field (B). Such a direct measuring technique is not yet available for the corona (Lin et al. 2004). Since almost all transient nonthermal radio emissions from the corona are either partially or fully circularly polarized, observing their polarization signatures over broad frequency ranges would be of help to estimate B as a function of heliocentric height. This article aims to describe the design and development of a Cross-polarized Log-Periodic Dipole Antenna (CLPDA), an integral part of a radio spectro-polarimeter, which works in the 50–500 MHz frequency-range and to explain the tests that were carried out to characterize it. The above frequency range corresponds to a heliocentric height range ≈1.03 < r < 2.5 R ⊙ ( R ⊙ = photospheric radius ), wherein the numerous coronal nonthermal transients associated with space-weather effects are observed to originate. The CLPDA is used to determine the strength and sense of polarization of the received radio signal. The uncertainty involved in the determination depends on the polarization-isolation (PI) between the two orthogonal components of a CLPDA. Some of the recent advancements made in the antenna design concepts at high frequencies (∼GHz) were adopted to reduce the PI at low frequencies (∼MHz). Throughout the above frequency range, the CLPDA has a gain, return loss, and PI of ≈6.6 dBi, ≲−10 dB, and ≲−27 dB, respectively. The average PI of the CLPDA varies from −30 to −24 dB over an azimuthal angle range 0° to ±45° within which the observations are performed regularly.
... The CALLISTO spectrometer is a programmable heterodyne receiver for solar observation developed in the context of IHY2007 and ISWI by the former Radio and Plasma Physics Group (PI Christian Monstein) at ETH Zurich, Switzerland [13]. CALLISTO is a program that is part of the IHY/UNBSSI and ISWI instrument deployment program [14]. It is a network that can continuously monitor the solar radio spectrum. ...
... The CALLISTO device has proved to be an extremely useful new method for tracking solar activity. Furthermore, it has evolved into a tool for determining solar radio emission from solar eruptions [14]. The goals of this study are to look into the levels of Radio Frequency Interference using e-CALLISTO stations, analyse it using the kurtosis process, and see if there is a relationship between population density and RFI level. ...
Radio Frequency Interference (RFI) has become a critical issue in radio astronomy observation in recent years. Compact Astronomical Low-Cost Instrument for Spectroscopy in Transportable Observatories (CALLISTO) is a worldwide network of spectrometer system for solar activity monitoring. The detection of solar radio bursts is being interrupted due to RFI as these stations are held on the ground. Since RFI signals are being detected from surrounding, this gives inaccurate data for ground base station observations. RFI sources are mostly from man-made devices. This paper study analysis of RFI level at selected CALLISTO stations by using Kurtosis Analysis. Data from Banting, Malaysia, Sumedang, Indonesia, Ooty, India and Daejeon, South Korea stations for two months (45–870 MHz) that contain solar burst and no solar burst had been selected. The kurtosis value is then compared with the population density to get the relationship between the population density and the RFI level. The highest average of kurtosis value indicates the lowest of radio frequency interference at these sites. MATLAB software was used for the data analysis and Microsoft Excel for the RFI profiling graphing. The results show that the high population density is not a main factor that contributes the interference towards the surrounding.
... The analog spectrum estimation is usually based on the application of a super heterodyne receiver that sequentially scans the frequency spectrum channel-by-channel and measures the signal power [18]. The modern digital methods are based on an application of the discrete Fourier transform (DFT) or computationally optimized fast Fourier transform (FFT) [19][20][21]. ...
... The technical requirements on the solar radio spectrograph were defined on the base of the long-term experiments with the current spectrograph with respect to the parameters of the similar instruments [17,18,24,25]. ...
... There are several existing projects of analog scanning and digital FFT based solar spectrographs [18,24,25,27,28], where usually prevails an approach of the reception, detection, and sensing of signal in the analog domain with a final conversion of the detector output to digital data for the storage and viewing. On the other hand, a modern digital spectrograph is de facto a wideband receiver equipped with the FFT processor for the signal spectrum calculation from samples produced by an analog-to-digital converter (ADC) working in baseband or intermediate-frequency band output of receiver. ...
The paper presents the concept, implementation, and test operation of a modernized solar radio spectrograph for an investigation of the solar emission and solar bursts in radio frequency bands. Besides having a strong diagnostic significance for studying the flare energy release, the solar radio bursts can also cause strong interference for radio communication and navigation systems. The current spectrograph for the Ondrejov observatory (Astronomical Institute of Czech Academy of Sciences) was modernized by using a direct-conversion receiver connected to a field-programmable gate array (FPGA) for the fast Fourier transform (FFT) spectrum estimation and put into the test operation. The higher time and frequency resolution and lower noise in comparison with the existing analog instrument were reached by the implementation of the latest optimal signal processing methods. To reduce the costs for such modernization, the operating frequency range was divided into four sub-bands of bandwidth 250 MHz, which brings another benefit of greater scalability. The first observations obtained by the new spectrograph and their comparison with the analog device are presented in the paper with future steps to put the spectrograph into the regular operation.
... The dielectric type "RT-duroid 5880" (with relative dielectric permittivity 1 Such parameters of the scattering matrix are determined from the condition of optimal matching of microstrip junction as an integral element of the radio frequency spectrometer of the stationary wave [14], which is used in determining the spectrum of radiation of remote galaxies in radio astronomy, and similar devices [15] - [16]. Calculations are carried out in the operating frequency range of spectrometer. ...
... The CALLISTO system has proven to be valuable new tool for monitoring solar activity. Besides, it has become an instrument for identifying the nature of solar radio emission from solar eruptions [7]. One of the uniqueness of the CALLISTO spectrometer network is, because of the collaboration of many countries, the Sun can be monitored 24 hours per day and all the data available online. ...
... The CALLISTO system has proven to be valuable new tool for monitoring solar activity. Besides, it has become an instrument for identifying the nature of solar radio emission from solar eruptions [7]. One of the uniqueness of the CALLISTO spectrometer network is, because of the collaboration of many countries, the Sun can be monitored 24 hours per day and all the data available online. ...
- This paper highlighted on the unique occurrence of the Solar Radio Burst Type III (SRBT III) during the high activities of the Sun. e- CALLISTO network is the system that responsible for the observation of the Sun 24 hours per day, which is a program under IHY/UNBSSI and ISWI instrument deployment program. The data was taken from one of the part of e-CALLISTO network which is Bleien, Switzerland. The event that had been selected was on 27th August 2015 since there was two subtypes of SRBT III can be obviously observed during the day within 12:00 UT till 12:05 UT. The current condition of solar wind speed is 348 km/s with density 8.4 protons/cm3. Besides the magnetic flux also quite high which is 13.4 nT. Regarding the detection of SRBT III, the x-ray flux data from Solar Monitor shows there is strong class m- flare also occur. The strong flare is also believed to have high temperature due to the high magnetic field. A geo-effective explosion was occur even though the sunspot no longer directly facing on the earth. The active region AR2403 was predicted can potentially cause radio blackout and radiation storm as long as the sunspot remains visible.
We report detailed observation of the ‘herring bone’ of a Type II solar radio bursts that occurred on November 3rd, 2010. Data from Space Weather Prediction Center National Oceanic and Atmospheric Administration (SWPC NOAA), e-CALLISTO, and Nancay RadioHeliograph (NRH) are analyzed. We determine the brightness temperature and degree of circular polarization of the ‘herring bone’ burst. Correlations between the physical parameters and the ‘herring bone’ are examined. Based on the relationship, this is the first study that suggested this ‘herring bone’ was generated through fundamental plasma.
Solar radio burst is defined as a massive solar radio emission related to the solar flare event occurrences. It is related to space weather events and will triggered an interference in our radio waves signal and affected the electromagnetic spectrum on earth. The solar flare could strike and condemn entire communications line including satellite operation, navigation system, Global Positioning System (GPS), international electrical grid and many more. Solar radio burst is the early warning sign that can helps reducing the effect by taking a precaution action by shutting down system. Because the solar radio is in the low frequency range, the detector system consist of low-frequency receiver is used to detect the burst event. As for Malaysia, solar radio observations are currently carried out using Compact Astronomical Low-cost, Low Frequency Instrument for Spectroscopy and Transportable Observatory (CALLISTO) which been placed at the Malaysia Space Agency (MYSA) Banting, Selangor. The application of Artificial Neural Network (ANN) helps in preparing the proper prediction on solar radio burst using solar radiation readings from the spectrometer. ANN is divided into two main group which are static and dynamic neural network. In static neural network, the data propagates in a single direction from input to the output whereas, in dynamic neural network, the data propagates regardless of its direction. In this paper, both static and dynamic neural network had been applied to the data obtained from CALLISTO to develop a solar radiation prediction model to detect the solar radio burst. Based from the results, it is shown that dynamic neural network given the best results compared to the static neural network.
Solar radio burst is one of the effects caused by the solar flare, which is directly related to the solar activities. Using the special-purposes spectrometers, the detection of solar radio burst can be achieved before the solar flare event took place. Solar flare can cause disruptions to our radio frequency spectrum and affected our technologies related to it, such as telecommunications network, Global Positioning System, and satellites applications. Compact Astronomical Low-cost Low Frequency Instrument for Spectroscopy and Transportable Observatory (CALLISTO) spectrometer had been widely used to detect the solar radio burst, thanks to the cooperative research around the globe. A brief review on the space weather, CALLISTO and solar radio burst detected using the spectrometers will be presented in this paper. This paper is constructed as a guideline for the further understanding on how CALLISTO could bring a significant contribution towards the solar radio burst detection in order to develop a reliable and a high-performance prediction system using the data gained from it.
