Radio Relay Stations Research Articles

Development of parabolic antenna irradiator for tropospheric communication station

The currently existing tropospheric stations, due to high energy consumption and limited signal formation capabilities, and radio relay stations, also due to limited communication range, require new technological solutions. One such solution proposed is the creation of a tropospheric-radio relay station with completely redesigned radio equipment. The Institute of Special Communications and Information Protection, in collaboration with a research institute, developed a scheme for such a station, which was tested in field trials on a real tropospheric radio line with a length of 155 km. Our specialists were involved in the development of two antenna devices. A detailed analysis of the current state of tropospheric communication station development in the world was conducted, and the possibilities of modernizing existing stations, such as the R-423-M, were considered. Based on the results of the analysis, it was proposed not to conduct modernization, but rather to develop a new generation of tropospheric communication stations. According to the accepted station construction concept, its transmitting and receiving parts were developed as two separate units (external and internal). The external unit for conducting field trials was located on the antenna, allowing for the maximum reduction of signal losses in the antenna-feeder paths. The components of the internal units were housed in the closed body of a vehicle. This provided additional convenience for the operator and reduced the requirements for climatic conditions. The antenna block of the transmitter includes a power divider, a power amplifier block (eight power amplifiers of 10 W each), a two-mirror parabolic antenna with a hyperboloid small mirror, and an eight-element horn feed that can be powered in such a way that the output wave will be either linear or circular polarization.

Structural models based on spectral graph theory for land-based digital communication networks

Problem statement. For the organization of digital communication networks in the range of meter and decimeter waves, as well as when providing communications based on them in hard-to-reach areas, problems arise related to maintaining the stability and continuity of information exchange between the switching nodes of the ground infrastructure. The existing approaches to solving these problems are based on the use of means of retransmission using radio relay stations and individual flight-lifting equipment. However, with limited deployment time, in emergency situations and when performing special tasks, these approaches are unacceptable for a number of objective reasons. Therefore, the search for ways to improve digital communication networks in the range of meter and decimeter waves is relevant and has important scientific and practical significance for ensuring the stability and continuity of information exchange by ground switching nodes in a given area. Purpose. To develop a structurally stable model of digital communication networks in the range of meter and decimeter waves based on a group of unmanned aerial vehicles, ensuring the organization of continuous information exchange of ground switching nodes in a given area for the required period of time. Results. Based on the results of the research, practical recommendations are formulated for their use to solve the problems of organization, restoration and redundancy, as well as the operational build-up of digital communication networks in the range of meter and decimeter waves for a given time interval in unfavorable operating conditions. The prospects for further research in the organization of the structural contour of the complex multi-circuit adaptation of digital communication networks for various purposes are determined. Practical significance. The results can be used by specialists in the field of satellite radio navigation in the development of local navigation systems.

Analysis of Wind Effect on Drone Relay Communications

In this study, we realized a relay network using drones and analyzed the impact of the sway angle of a drone’s attitude on communication in a windy flight environment. Drones in flight act as radio relay stations and communication among them is performed using radio equipment mounted on board. In a windy environment, a directional antenna is used for relay communication among them to avoid interference caused by the spread of radio waves in space and extend the relay distance. However, when wind occurs during flight, the flying attitude of the drone inclines, which causes the beam of the antenna to sway and the communication link to be disconnected, leading to a decrease in the transmission speed. In this study, we statistically evaluated the pitch, yaw, and roll axes of a drone through wind tunnel experiments. Furthermore, the pattern of the swing angle of the drone with respect to the wind speed was investigated using computer simulations to analyze the fluid dynamics and theoretically analyze the swing of the drone. Based on these results, the transmission speed when using a directional antenna was calculated. When the wind speed was 6.0 m/s, the pitch axis deflection angle of the drone was 13∘ at maximum, and the average transmission speed decreased by 33.3 Mbps. In this study, it was found that in communication between drones due to the wind, the transmission efficiency decreased depending on the sway angle of the aircraft.

ЗАСТОСУВАННЯ ПРОСТОРОВОЇ ОБРОБКИ В СИСТЕМАХ ЗВ’ЯЗКУ Й ПЕРЕДАЧІ ДАНИХ КОМПЛЕКСІВ РАДІОМОНІТОРИНГУ ДЛЯ ЗАБЕЗПЕЧЕННЯ ЗАВАДОЗАХИЩЕНОСТІ

The article investigates the issue of improving the level of environmental in communication systems and data transmission of radio monitoring complexes. The relevance of this task is due to the complexity of the modern electronic environment, which is characterized by high dynamics and saturation with electronic means that work on radiation and have a mutual impact, as well as the importance of tasks performed by military radio monitoring units. The paper proposes the use of the algorithm of multichannel weight spatial processing of signals against the background of interference to improve the obstruction of communication systems and data transmission on the basis of the radio relay station "R-415V". This approach is the most rational, since the compensation of existing obstacles is carried out subject to the presence of spatial differences between the directions of the arrival of a useful signal and the obstacle that it is typical for radio relay stations. In addition, the technical prerequisite for the implementation of the proposed solution is the presence in the radio relay station "P 415V" of the directional antenna "DB11", consisting of two identical z-emitters and is the simplest two-element antenna grille that can be used to implement multichannel weight treatment. The article presents the spatial processing algorithm, selected performance indicators and investigated the effectiveness of its work. The calculations were carried out using the computer algebra system – Mathcad 15. Were obtained visual, quantitative and qualitative results of performance indicators depending on the selected electronic situation for certain tactical and technical characteristics of the means of transmitting information without taking into account the influence of destabilizing factors on the quality of processing.

Calculation apparatus for modeling the distribution of electromagnetic fields of different sources

The calculation apparatus acceptable for assumptions and simplifications and sufficient for errors of final results for modeling the propagation of electric, magnetic and electromagnetic fields spread over a certain area was proposed. It is shown that to model the propagation of ultra-low frequency electric and magnetic fields (monitors, uninterruptible power supplies, transformers, electric motors and generators) it is possible to consider these sources as dipole and dipole-quadrupole type sources. That is, the field of the local source can be considered as a combination of electric and magnetic dipoles. This makes it possible to delineate with sufficient accuracy the zones of exceeding the maximum allowable field strengths. The calculation apparatus used to determine the radiation intensities of civil aviation radar equipment was adapted to model the propagation of electromagnetic fields of very high and ultra-high frequencies. The calculations of coefficients that take into account the parameters of radiation patterns in the horizontal and vertical planes for the most common radiation sources are given. These ratios and corresponding coefficients can be used to determine the electromagnetic environment in the presence of many high-frequency sources (mobile communication base stations, navigation equipment, radio relay stations, etc.). The proposed approach allows to automate processes of designing the placement of electromagnetic, electronic and radio equipment in production areas and territories, as well as to assess the environmental impact at the stages of design work. This will make it possible to delineate the isolines of the limits of exceeding the maximum permissible levels of electric magnetic and electromagnetic fields for different frequency ranges and categories of equipment and to automatically determine the electromagnetic load at each point of the controlled space.

Electromagnetic Radiation Safety: Russian National and International Regulatory Frameworks for Radiofrequency Electromagnetic Fields

Summary. Introduction: Today, the growing human exposure to radiofrequency electromagnetic fields is of serious concern to the population and the international scientific community. Sources of radiofrequency electromagnetic fields in residential areas include mobile radio base stations, signal repeaters, wireless broadband access points, TV and radio transmitters, satellite earth stations, radar and radio relay stations. Launching of 5G mobile networks will further complicate the electromagnetic situation in inhabited areas, especially in megacities where the size of exposed population is the largest. In the system of measures contributing to protection of the population from adverse health effects of electromagnetic fields, standards (regulations and other documents establishing electromagnetic fields permissible levels) play a significant role and lay the foundation for organizational and technical measures of protection. High importance of standards in ensuring electromagnetic safety served as the basis for our study. The objective of the study was to perform a comparative analysis of radiofrequency electromagnetic fields standards for inhabited areas and approaches to setting electromagnetic fields exposure levels adopted by different countries and international organizations. Methods: We reviewed of some aspects of biological effects of radiofrequency electromagnetic fields, regulations setting electromagnetic fields exposure limits in different countries and recommended by ICNIRP, and approaches to establishing those limits. Conclusions: We found a significant discrepancy in radiofrequency electromagnetic fields limits adopted in different countries, the legal status and scope of regulatory documents. Differences in the methodology for the development, adoption and approval of electromagnetic fields standard accompanied by differences in their legal status prevent uniform EMF standard setting.

Evaluation and Substantiation of the Necessity to Revise Guidelines for Measuring Electromagnetic Radiation of Cellular Base Stations

Introduction: Measurements of electromagnetic radiation of the radio frequency range are of great relevance due to the increasing number of transmitting radio facilities in the densely populated territories, constant cell site upgrades, and emerging communication standards. The paper presents a brief description of the biological effects of radio frequency electromagnetic radiation and shows basic mechanisms of the negative effect on the most vulnerable organs and systems. Our objective was to evaluate valid guidelines for measuring electromagnetic radiations of the radio frequency range in residential areas, in houses and public buildings. Materials and methods: We reviewed specific characteristics of cellular base and radio relay stations, compared and described electromagnetic radiation measuring devices. The provided recommendations for their selection were based on frequencies at which the communication equipment operates. We also analyzed the current guidelines with account for characteristics of transmitting radio equipment of cellular base stations and the applied measuring instruments. Results: The results of assessing established significant differences are discussed. The analysis of the requirements for measurements demonstrated significant discrepancies and contradictions between the valid documents. The evaluation results demonstrated impossibility of simultaneous measurements of electromagnetic radiation from cellular BS and RRS due to violations of requirements for measurement procedures. We concluded that, according to the current method documents, measurements of electromagnetic radiation from the fourth (4G) and fifth (5G) generation mobile communications systems were not possible. Conclusions: We revealed the necessity to revise the compared guidelines МUК 4.3.1167–02 and МUК 4.3.1677–03, to harmonize regulatory requirements for measurements, and to develop a single document guiding measurements of radio frequency electromagnetic radiation. Recommendations for taking measurements are provided.

The analytical look of the current technologies of the tropospheric and radio-relay

The relevance of the task of creating a mobile combined station of digital tropospheric and satellite communications of the microwave range, which simultane­ ously operates in 2 modes: horizontal communication and direct visibility, substantiates an analytical review of the current state of tropospheric communication in the world. The technical characteristics of the advanced developments of digital troposphere stations and control systems of foreign companies Comtech Systems, Raytheon Corporation, General Dynamics, Advantech Wireless are presented. It is shown that the RTM-100 tropospheric modem, with a bandwidth of 50 Mbit/s and more, which provides stable communications under multipath conditions when using direct error correction turbocompression (FEC) and supports work with Gigabit Ethernet (GbE) data ports and SNMP protocol is the key Elements for creating a new mobile combined digital troposphere and satellite communications station. The analysis of the current state and development trends of radio-relay communication, as well as the spectrum of widespread use of modern digital radio-relay communication. The OptiX RTN 900, a new generation of IP-based digital radio relay system with a split structure, is one of the first systems to support TDM, packet and hybrid transmission platforms. The system supports communication in 2G networks, voice and data services in 3G networks, broadband data services in LTE networks. Radio relay systems of NEC, NERA, Huawei Technologies, ZTE, Nokia Siemens Networks (former Alcatel-Lucent) companies implement adaptive modulation and coding (Adaptive Coding & Modulation — ACM), which allows you to change the parameters of the radio channel when changing the propagation conditions of radio waves and thereby technology AFM allows the operator to reduce their capital costs during the construction of RRL by installing antennas of smaller diameters or by building longer communication intervals. The bandwidth of digital radio relay stations has grown to 5.5 Gb / s (Ericsson) and for this new sections of the millimeter wave range have been mastered: 71…76 GHz, 81...86 GHz. The development of the terahertz frequency range opens up great op­ por­ tunities for a significant increase in throughput and security and secrecy. An analytical analysis showed the promise of creating a mobile combined station of the digital tropospheric and satellite microwave range, corresponding to the development trends of tropospheric and microwave radio communications, is an urgent task for Ukraine.

ANALYSIS OF THE STATE OF THE CURRENT ELECTROMAGNETIC SAFETY FOR CREWS OF THE ICEBREAKING FLEET VESSEL

Introduction. The article presents results of a study on the hygienic evaluation of the impact of levels of electromagnetic fields (EMF) from electrical equipment, communications and navigational aids on modern automated ice-breaking vessels to the electromagnetic safety of the crew. Material and methods. The instrumental measurement of EMF levels from power equipment, electronic equipment, computers, were conducted in places of a permanent and temporary stay of the crew watches in parked icebreakers in the port and during sea trials. The assessment of the levels of electromagnetic radiation from the antennas of radio relay stations (radar) was conducted using the forecasting parameters of the EMF. Results. Onboard computers, marine electrical, communications and radar transmitters do not create electromagnetic fields exceeding the RC in crew workplaces of ship premises. Levels of EMF SHF range generated by RADAR antennas on the open deck, also do not exceed RC. Electromagnetic fields exceeding the RC are registered at work communications transmitters VHF, MF/HF on the decks of the installation of antennas transmitting devices. Discussion. There is a relevant matter of the protection of the crew from the EMF generated by the antennas of modern radars. Evaluation of the EMF RADAR intensity is only possible on the basis of data on forecasting levels of the electromagnetic radiation. To protect the crew from the EMF generated by antennas means the marine radio and RADAR on open decks should implement measures to limit exposure time to install warning signs and placards. Conclusions. There is required the improvement of normative-methodical documents in the field of the protection of the crew from the EMF. You must create a measurement technique for recording the intensity of electromagnetic radiation from the radar. Research data can be used for the development of science-based sanitary-epidemiological requirements for electromagnetic safety of the crew.

Analysis of modern condition of military radiocommunication system

Aim of the article is to conduct an analysis of military communications systems that were used in the area of conducting antiterrorist operation in theDonetsk and Lugansk regions. The article analyzes the modern facilities of military communication, namely: military radiocommunication systems, military satellite communication systems, military systems of radio relay and tropospheric communication. The advantages and disadvantages of each type of communication are considered, the causes of their occurrence were considered, and the ways of solving these reasons in the future were substantiated. An analysis of the main technical characteristics of military communication systems, opportunities, advantages and disadvantages has been conducted. The perspectives for the development of military communication systems have been determined on the basis of the analysis of the military facilities of communication used in the article, which are used in the region of the antiterrorist operation in theDonetsk and Lugansk regions. To eliminate the problematic issues mentioned in the article, the authors of the article are proposing to launch their own military satellite for the needs of the Armed Forces of Ukraine; To develop new models of military communication; To conduct deep modernization of the existing radio stations, command-staff cars, radio relay and tropospheric stations; To integrate telecommunications equipment adopted in the last years into a single information space of the Armed Forces of Ukraine, as well as to reach agreement with representatives of leading telecommunication equipment manufacturers regarding the transfer of technologies and deployment of production in the territory of Ukraine.

A Dual-Channel MEMS Amplitude Demodulator for On-Line Detection in Radio Relay Station

A dual-channel amplitude demodulator based on a micro-electromechanical systems (MEMS) approach for radio relay station on-line detection is proposed in this letter. This MEMS demodulator adopts a clamped-clamped beam to couple part of the signal from the main line to dual channels for on-line amplitude demodulation. The MEMS-based demodulation applies the square law of the thermal converter. The fabrication of the device is compatible with GaAs monolithic microwave integrated circuit process. Experiments show that the on-line MEMS demodulator has a return loss that is better than 20 dB, and an insertion loss of less than 0.5 dB up to 10 GHz. This design can realize direct demodulation of an amplitude modulation signal with a carrier frequency of 0.01-10 GHz.

MODEM EQUIPMENT FOR THE NEW GENERATION COMPACT TROPOSCATTER STATIONS

Background. Modem equipment of tropospheric communication lines is an important component of modern means of telecommunication. The theoretical and practical aspects of choosing a preferred embodiment of modem equipment, taking into account the aggregate indicators of quality.Objective. Presentation features the construction of modem equipment of the tropospheric stations of new generation that can provide high data transfer rates with guaranteed quality of service in complex stationary and non-stationary noise inherent in tropospheric channels.Methods. This goal is achieved by using new technical and architectural solutions to build a modem equipment, spectrally efficient modulation types and coding algorithms of effective adaptation to changing operating conditions. Feasibility of the proposed approaches to the construction of the modem hardware is fulfilled on a prototype of the equipment based on the HSMCARRadio Daughter Card debugging modules.Results. The features of constructing of modem equipment of troposcatter stations with high data transfer rate are provided. To reach the limiting parameters of such stations proposed in the application of modem equipment of new technical and architectural solutions, spectrally efficient modulation types (OFDM plus linear modulation) and error-correcting coding, efficient algorithms of adaptation to changing conditions of work, the SDR technology, frame structures of physical layer. The variants of the configuration of modem equipment in relation to the modes of operation of compact troposcatter station.Conclusions. Ways of improving modem performance to improve the efficiency of modern compact troposcatter radiorelay stations.

The Modem Equipment Based on SDR-Technology for New Generation Tropospheric Stations

Background. Modem equipment of tropospheric communication lines is an important component of modern means of telecommunication. The theoretical and practical aspects of choosing a preferred embodiment of modem equipment, taking into account the aggregate indicators of quality.Objective. Presentation of features of the modem equipment construction of new generation tropospheric stations that can provide high data transfer rates with guaranteed quality of service in complex stationary and non-stationary noise inherent in tropospheric channels.Methods. The goal is achieved by using new technical and architectural solutions to build SDR based modem equipment, spectrally efficient modulation types and coding, algorithms of effective adaptation to changing operating conditions. Feasibility of the proposed approaches to the construction of the modem hardware is fulfilled on a prototype of the equipment based on the HSMC ARRadio Daughter Card debugging modules.Results. The features of constructing of modem equipment of troposcatter stations with high data transfer rate are provided. To reach the limiting parameters of such stations the application of modem equipment of new technical and architectural solutions, spectrally efficient modulation types (OFDM plus linear modulation) and error-correcting coding, efficient algorithms of adaptation to changing conditions of work, the SDR technology, frame structures of physical layer was proposed. The configuration variants of modem equipment in relation to the modes of operation of compact troposcatter station were proposed.Conclusions. The proposed ways to improve the effectiveness of modem equipment allow realizing compact troposcatter radiorelay stations with a high rate of data transmission.

1A1-U09 福島第一原発での教訓を踏まえた突入撤退判断システム(第3報) : 遠隔操縦のための無線中継局設置機構の開発

We have been proposed Attack and Retreat Judgment System for fire rescue task force referring the lesson from Fukushima Daiichi nuclear power plant. The proposed system is consist from 2 parts. The remote-controlled surveillance system, which gather the information of radiation dose, gas concentration. And the rescue task force's equipment with wearable vital sensors and environmental sensors. The both system need to communicate to the command post. Therefore, wireless communication network in wide-area is necessary, and mobile radio relay station can achieve communication network. In this paper, we proposed radio relay station for remote-controlled surveillance system.

Applying FDTD Simulation to Lightning Surge Route Analysis in Microwave Relay Stations

Microwave multiple radio relay stations are often built on mountains, and the stations are susceptible to damage from lightning. Therefore, it is important to take adequate lightning protection measures to ensure that communication devices are not damaged by any lightning surge current that penetrates from a lightning rod fitted on such stations. In most cases, the penetration route of the lightning surge current is uncertain, and it is difficult to specifically evaluate the effectiveness of measures against lightning. We calculated the branch aspect of lightning surge current in actual microwave relay stations using the finite difference time domain (FDTD) method, which is one way to numerically analyze electromagnetic fields, to directly solve Maxwell's equations. By comparing the calculated results with measured results obtained by injecting a pulse current into a microwave relay station, we verified that the current peak value of the calculated results corresponded with the measured results well, both when a steel tower was located on the ground and when it was located on the roof of a microwave relay station. We confirmed that the FDTD method can be used to understand the branch current of lightning surges and to study lightning protection measures at microwave relay stations.

The development of norms of frequency-territorial separation of digital broadcasting and television of standard T-DAB and DVB-T with thin-route radio relay stations

The development of norms of frequency-territorial separation of digital broadcasting and television of standard T-DAB and DVB-T with thin-route radio relay stations

Cardiovascular risk in operators under radiofrequency electromagnetic radiation

The aim of the study was to assess the long-term effects of radiofrequency electromagnetic radiation (EMR) on the cardiovascular system. Two groups of exposed operators (49 broadcasting (BC) station and 61 TV station operators) and a control group of 110 radiorelay station operators, matched by sex and age, with similar job characteristics except for the radiofrequency EMR were studied. The EMR exposure was assessed and the time-weighted average (TWA) was calculated. The cardiovascular risk factors arterial pressure, lipid profile, body mass index, waist/hip ratio, smoking, and family history of cardiovascular disease were followed. The systolic and diastolic blood pressure (SBP and DBP), total cholesterol (TC) and low-density lipoprotein cholesterol (LDL-C) were significantly higher in the two exposed groups. It was found that the radiofrequency EMR exposure was associated with greater chance of becoming hypertensive and dyslipidemic. The stepwise multiple regression equations showed that the SBP and TWA predicted the high TC and high LDL-C, while the TC, age and abdominal obesity were predictors for high SBP and DBP. In conclusion, our data show that the radiofrequency EMR contributes to adverse effects on the cardiovascular system.

Characteristics of a highly efficient propeller type small wind turbine with a diffuser

We studied the improved effects a diffuser had on the output power of small wind turbine systems, aiming to introduce these systems to radio relay stations as an independent power supply system. A frustum-shaped diffuser was chosen from an economical standpoint and wind speed distribution. The effect the diffuser's shape had on the wind speed was analyzed by simulation and showed that the wind speed in the diffuser was greatly influenced by the length and expansion angle of the diffuser, and maximum wind speed increased 1.7 times with the selection of the appropriate diffuser shape. The wind speed in the diffuser was fastest near the diffuser's entrance. We conducted field tests using a real examination device with a diffuser and confirmed that the output power of the wind power generator increased by up to 2.4 times compared to that of a conventional turbine. Moreover, it was confirmed that the diffuser was especially useful where the wind direction was constant.

Accident on Mount McKinley

Accident on Mount McKinley

Comparison of chromosome aberrations in peripheral blood lymphocytes from people occupationally exposed to ionizing and radiofrequency radiation.

The genotoxic effects of occupational exposure to ionizing and non-ionizing radiation were investigated in 25 physicians and nurses working in hospitals and in 20 individuals working at radio-relay stations. Examination was conducted by chromosome aberration analysis of peripheral blood lymphocytes. The data showed that total number of chromosome aberrations in people exposed to ionizing and radio-frequency radiation (4.08 +/- 0.37 and 4.35 +/- 0.5 on 200 scored metaphases, respectively) were almost equally higher than those of non-irradiated subjects. The increase was in proportion to the number of individuals having more that 5-aberration/200 metaphases. Acentric fragments comprised the most frequently seen type of aberration. The average numbers in examined groups (11.8 x 10(-3) and 14.8 x 10(-3) per cell, respectively), were significantly higher than 4.2 x 10(-3), which was observed in controls, unexposed individuals. Dicentric fragments were also frequent (4.8 x 10(-3) and 6.25 x 10(-3), respectively, vs. 0.52 x 10(-3) in control). In contrast, the frequency of chromatid breaks increased only after ionizing radiation (3.8 x 10(-3) vs. 0.26 x 10(-3) in control). A positive correlation between the total number of chromosome aberrations and cumulative 6-years dosage was also found. The data emphasized the dangerous effects of prolonged exposure to both types of radiation and indicated that chromosomal aberration analysis should be obligatory for individuals working at radio-relay stations.