Antenna Towers Research Articles

SISTEM PENANGKAL PETIR DI GEDUNG TELEKOMUNIKASI DAN GEDUNG PAI MATSC

On Friday, 11 November 2022, there was damage to the radio link equipment in the HF and MSSR radio transmitter communication systems due to a lightning strike operating at the Makassar Air Traffic Service Center (MATSC) office. This lightning strike is a phenomenon that poses a threat to the operation of flight navigation services carried out by the MATSC branch of Perum LPPNPI. The purpose of this study is to evaluate the external lightning protection system that has been installed and also to determine the effectiveness of the conventional lightning protection system on the antenna tower next to the MATSC radio PAI building. This study uses quantitative research methods. Retrieval of data using the method of observation and measurement. The calculation results found that the PAI Building was included in category IV, meaning that the lightning strike hazard level is 80%. While the antenna tower has a protection level category III, which means it has a danger level of 90%. However, from the observations, only the tower antenna is provided with a conventional type of lightning rod, while the PAI Building does not have a lightning rod system. The calculation results show that the existing conventional lightning rod protection angle is around 35o with a protection radius of 16.58 m. So that with this radius, the PAI building does not fully get protection from the dangers of lightning strikes.
 
 Keywords: Lightning Protection System, Antenna Tower, PAI MATSC Building

Hybrid deep learning model for efficient prediction of telecom data using EMF radiation

EMF has a variety of biological impacts and has an impact on the metabolic process in the human body. Antenna towers, anechoic chambers, and other sources can all produce this. Some of the human populations live very close to the EMF-emitting antenna towers. We can make humans aware of the EMF radiation and protect from diseases if there is a proper method to anticipate the EMF radiation of antennas installed in different places. For the study of telecom data and EMF emission, many machine learning and deep learning techniques have been developed in recent years. Predictive analytics played a bigger part in this. For prediction, it comprises advanced statistics, modeling and more machine learning methodologies. However, the appropriate hyper parameters must be established for the model’s effective prediction, but this cannot be guaranteed in a dynamic environment where the data is always changing. The learning model’s performance improves when these parameters are optimized. The goal of this study is to use the Telecom dataset to create a novel hybrid deep learning model for forecasting the trend of EMF radiations. The patterns were first discovered using Artificial Neural Networks (ANN) and Multilayer Perceptron (MLP) combined with the Particle Swarm Optimization method (PSO). Later to boost its performance the hybrid approach (MLP-RFD-PSO) was developed and 98.8% accuracy was achieved.

Assessment of the Elastoplastic Nonlinear Static and Dynamic Behavior of Guyed Antenna Towers Subjected to Cable Rupture

AbstractCable‐stayed antenna towers are slender structures composed of a central mast and several cable levels and exhibit a highly non‐linear behavior under static and dynamic loads, due to the mast‐cable interaction and the tower height. Many accidents reported in literature are due to cable rupture. Thus, the aim of the present work is to study the effect of cables rupture and plasticity on the load capacity, stability and nonlinear oscillations of a cable stayed tower considering the influence of both geometric and material nonlinearity. For this, finite element models of cable‐stayed towers with two levels of pre‐tensioned cables are developed, considering both fan and parallel cable distributions. Initially, the linear behavior of the structure is evaluated through the natural frequencies and critical loads. Next, the non‐linear equilibrium paths of each model are obtained, applying the concept of modal imperfection. Finally, forced free and damped vibration analyses are performed. For this, time responses, phase plane projections, Fourier transforms and spectrographs are used. The results confirm and quantify the strong influence of the loss of one or more cables on the response of the guyed tower.

Natural frequencies and mode shapes in zero-force members of a truss

Trusses are everywhere; they are used in bridges, antenna towers, cranes, even in parts of the International Space Station. And for good reason, they allow us to create strong structures while using materials in very efficient and cost-effective way. Trusses it is essentially a rigid structure made up of a collection of straight members. The type of truss depends on how the horizontal and diagonal beams are arranged.

Non-Ionizing Radiation Analysis in Close Proximity to Antenna Tower: A Case Study in Northeast Brazil

Abstract While the amount of telecommunications services grows rapidly in the whole world, humans get potentially more exposed to Non-Ionizing Radiation (NIR) from a number of different sources. Measurements of NIR levels are relevant in order to compare the results with national and international standards, aiming at the preservation of human health. Thus, it is of great interest to explore a variety of topics regarding this subject. Based on this need, this paper has a number of goals, including monitoring radiation levels in an everyday situation, an investigation of how national and international regulations organs address NIR levels and a demonstration of scientific production trends regarding this topic. The work also presents a bibliometric study about the main scientific productions and trends related to NIR measurements, with focus on the field of Telecommunications. The analysis is based on the databases of Web of Science (WOS) and Scopus, computing publications in the last 10 and 3 years, showing a trend evaluation. Among the main results from this exploratory investigation, there is an exponential growth in the number of publications about NIR, ranging from research in physics to medicine. The way research contribution in different countries is also shown, in order to support the relevance of the topic in defining new tendencies for new investigations. Furthermore, the NIR exposure limits and measurement criteria are presented both in Brazilian and in international norms, demonstrating how different national regulations can be when compared to international guidelines. Another contribution is a case study in Natal, Brazil, where NIR levels were monitored in four distinct locations over a period of 24 hours each and compared to the current regulations. The result is a quantitative analysis of the amount of radiation that some populations might be exposed to in distinct moments of the day. Measurements were carried out in the proximity of an antenna spot, since it could represent a source of high NIR levels (a worst case of human exposure). This campaign differs from older studies by including a more intense usage of microwaves frequencies due to operating 4G and pre-5G systems in Brazil. Finally, a statistical study involving the measurements is conducted, concluding the analysis of how some population groups might be affected by NIR.

Lightning Protection for Mobile Phone Base Stations by Combining λ/4 Short Stub and λ/4 Open Stub

This paper describes lightning protection for mobile phone base stations by combining quarter wave short and open stubs. MPBS (Mobile Phone Base Stations) have antenna towers and are often installed on the top of mountains. Therefore they have a high probability of lightning strikes.The most important lightning protection system is a bonding network and an earth system. All incoming services should be bonded at the entry to the MPBS in order to obtain an equipotential environment for all systems. And SPD (Surge Protective Device) should be installed at the entry to the BTS（ Base Transceiver Station）. As an SPD, either a GDT or λ/4 short stub was used. However, conventional SPD such as a GDT and λ/4 short stub cannot completely prevent the lightning surge current diverging to the BTS side. Therefore we have developed an insulated coaxial SPD that allows lightning surges to be discharged to the ground while passing signals without loss by combining the λ/4 short stub and the λ/4 open stub. The performances of this newly developed product were as follows. Insertion loss was less than 0.1dB, VSWR was less than 1.15 and voltage protection Level Up was 80V

Engineering critical assessment of steel shell structure elements welded joints under high cycle fatigue

Existing flaws in critical parts of structural elements may lead to failures of subassemblies and, in case of lack of redundancy, even to the entire structure collapse. Considering the case of cyclic loading – wind load (including extreme phenomena as storms or blizzards), in which some of these type of structures have failed/collapsed, the post factum assessment, indicated the principal damage causes, i.e. existing welding flaws in combination with corrosion (surface flaws). The paper presents the fitness-for-purpose analysis, i.e. Engineering Critical Assessment, applied during design, in order to assist in the choice of welding procedure and/or inspection techniques. The evaluation is made with BS7910/2013 standard using level 2 failure assessment diagrams for possible discovered flaws, considering a real case assessment – a new designed steel monopole type antenna tower structure.

Review design of wind load analysis structures guyed tension in the Bogor repeater radio frequency antenna towers

The purpose of this study is to analyze the wind load on the Repeater Radio Frequency (RRF) antenna tower, the wind load is viewed from an angle of 0° to the towing cable to the largest angle on the two types of antenna towers, triangle and rectangular. Both types will produce different wind loads so that we can find out which load is the biggest from a combination of wind directions. The research method is by empirical analysis, calculating the wind load alone while other loads are not counted. As a result of wind loads, the tension cable and load direction correspond to each section and then the resultant values of force and direction will arise. And finally, the force is changed to lift and the anchor will hold the force. The results; The use of triangle antenna towers is more beneficial, especially the wind load that occurs is smaller, thus the construction costs are also smaller. The lifting power of a triangle antenna anchor tower is lighter around 1393.971N or 1.393971kN than that of a square antenna anchor tower lift of around 1971.373N or 1.971373kN.

Experimental Investigation for Effects of Mini-piles on the Structural Response of Raft Foundations

Mini-piles made their debut as a cost-effective way to stabilize the historical structures. Recently, mini-piles have increased in popularity all over the world and are being used for bridges, buildings, slope stability, antenna towers, and residential construction. This paper presents the preparing, executing, data acquisition, and result presentation for an experimental work concerns with five scale-down mini-piled raft foundation models. All models were prepared to study the effectiveness of the mini-piled raft foundation in reducing the settlement and the bending moments. Five tests have been achieved. The reference first test includes a raft foundation with 15mm thickness. Second, third, and fourth tests are mini-piled raft foundations with five mini-piles and with thicknesses of 15 mm, 10 mm, and 8mm respectively. Finally, the fifth test dealt with a single mini-pile 178mm in length and 6mm in diameter. It has been adopted to investigate the reference behavior of the single mini-pile. When they were used, the piles have 42 mm center to center distances. A scale-down factor of , a sandy soil with with of , and relative density of 60% have been considered in all tests. Test results indicated a 45% decrease in settlement for 15mm mini-piled raft foundation comparing with the reference 15mm raft foundation. Moreover, there is no significant difference in settlement between 15mm mini-piled raft foundation comparing with the 10mm and 8mm thick mini-piled raft foundations. Regarding to the bending moments, they decrease at the mid and edge of the 15mm mini-piled raft foundation comparing to those of the reference raft foundation. It has also been noted that the moments are inversely proportional to the thickness of the piled raft foundations. With respect to the mini-piles, it has been found that most of the pile axial loads are transferred to the underneath soil through friction and this friction increases as the raft thickness decreases.

Steel antenna towers – from designing to manufacturing optimization

The elaboration of a methodology for determining the acceptability of detected cracks/flaws in a structure has a major practical importance in the overall assessment and life integrity of a structure. The relation given by fracture mechanics links a parameter which describes the stress intensity at a crack tip to a material characteristic – fracture toughness. This relation provides the possibility of assessing the fracture conditions of the structural elements with defects (cracks). An Engineering Critical Assessment is an analysis based on fracture mechanics principles, of whether or not a given flaw is safe from brittle fracture, fatigue, creep or plastic collapse under specified loading conditions.The paper presents some considerations on the designing and manufacturing process, taking into account structural assessment procedures using fracture mechanics. It also presents a study case – a steel monopole tower on which the method is applied, in order to assessing the possible discovered flaws in the designing phase. Ten types of flaws which can be discovered in the service time of the structure were assessed. Different types of locations were taken into account, thus resulting groups of flaws which were then assessed and compared.

Long-range and energy-efficient optical networking for tiny sensors

Acquiring real time sensory data using remote swarms of tiny sensors depends on efficient wireless networking. Often, battery longevity of the sensors is a critical design requirement, which makes long-range RF transmission inadequate for this task. A common solution is to use short-range and energy-efficient RF protocols within the swarm, then communicate with the outside world via a capable agent or a networking gateway. In this paper we suggest an alternative networking model, which enables the swarm to operate independently, without the assistance of an intermediate proxy. Specifically, we present a networking model in which the sensors in the swarm transmit data using energy-efficient free space optical links (FSO). We discuss the details of aiming optical transmission interfaces in the directions of distant sinks, such as antenna towers, drones and even LEO-satellites. This FSO-based network architecture poses various data collection problems, which are related to the directional nature of optical transmitters and receivers. Using simulations we address several such problems, and demonstrate the viability of the model for sensory data collection.

System-reliability analysis of steel truss towers

Steel truss towers are important structures in civil engineering, used as, for example, antenna towers, architectural towers, transmission towers, chimney towers, light towers, viewing towers, or water towers. In the paper, the latter structural type is analysed. Three types of truss towers with different topology are discussed. The towers are designed according to the standards. Next, reliability analysis is performed and the influence of type of truss topology on reliability is analysed. Reliability analysis concerns formulation of the limit state, calculation of failure probability and determination of reliability index. In the paper, the system approach is proposed, definitely more complete than that obtained using approximation-simulation methods. In the case of structures analysed in the paper, the types of reliability models are determined. Identification of reliability models relies on studies on the transformation of the safe structural system into the geometrically variable system (mechanism). The investigations made it possible to determine the kinematically admissible failure mechanisms which contain minimal critical sets of elements. In order to identify the mechanism, spectral analysis of the linear stiffness matrix is used. In the case of the towers of concern, the formulas specifying the number of mechanisms for any number of repeating sections are determined.

Measurement-Based Evaluation on Detection Probability of Extended Squitter for Air-to-Ground Surveillance

Deployment of Automatic Dependent Surveillance—Broadcast (ADS-B) has commenced worldwide for aeronautical surveillance. In ADS-B, an aircraft broadcasts extended squitters, which include its position measured by the Global Navigation Satellite System. These squitters are received by ground stations. ADS-B has the potential to achieve higher accuracy and higher update rates than conventional radar, however, they are vulnerable to co-channel interference. Therefore, evaluating the performance of extended squitters in real interference environments is crucial for successful deployment of ADS-B, the goal of this work. Our approach is to gather and analyze measurement data from four experimental ground stations in the Kanto airspace, Japan. The measurement data are practical as the sites include two major airports and an antenna tower supporting air-ground communication. Analysis of the data yields a measurement-based model that can estimate the probability of detection of the extended squitter for given link-margin and interfering signal rate. To the best of the our knowledge, this is the first work to derive an expression for the probability of detection based on large-scale measurements. Two applications of the model are demonstrated. First, the improvement on performance made possible by using a sector antenna instead of an omni-directional antenna is predicted; the contributions of improved link-margin and reduced interference are given. Second, the ADS-B coverage is predicted along an experimental flight route.

Antenna Towers Attract Additional Lightning Strikes

Atmospheric scientists evaluate the influence of human-made structures on lightning data.

Antenna structures and cloud‐to‐ground lightning location: 1995–2015

AbstractSpatial analyses of cloud‐to‐ground (CG) lightning occurrence due to a rapid expansion in the number of antenna towers across the United States are explored by gridding 20 years of National Lightning Detection Network data at 500 m spatial resolution. The 99.8% of grid cells with ≥100 CGs were within 1 km of an antenna tower registered with the Federal Communications Commission. Tower height is positively correlated with CG occurrence; towers taller than 400 m above ground level experience a median increase of 150% in CG lightning density compared to a region 2 km to 5 km away. In the northern Great Plains, the cumulative CG lightning density near the tower was around 138% (117%) higher than a region 2 to 5 km away in the September–February (March–August) months. Higher CG frequencies typically also occur in the first full year following new tower construction, creating new lightning hot spots.

Reviewing and Classifying the Effective Factors in Selection Telecommunication Antenna Towers Sites.

Reviewing and Classifying the Effective Factors in Selection Telecommunication Antenna Towers Sites.

Development of a shunt lightning current measuring system using a Rogowski coil

Recently, the amount of lightning damage has increased with the number of lightning flashes. Therefore, it has become important to understand the features of lightning current damage to electrical and electronic equipment. At wind-turbine sites and tall antenna towers, lightning current waveforms are observed using large-scale Rogowski coils. Data related to the main current measured by the large-scale Rogowski coils and the shunt current that damages the electrical and electronic equipment are useful to establish lightning protection methodologies. In this paper, we present a system developed using a Rogowski coil to measure this shunt current.

Current distribution and transient magnetic fields in an observatory of TOKYO SKYTREE

TOKYO SKYTREE is the tallest free-standing antenna tower; whose height is 634m. However, the number of lightning strikes to a tall structure increases in proportion to the structure height. Therefore, it is important to establish lightning protection methods for facilities in and around such tall antenna tower.There is a possibility that comparatively large magnetic fields occur inside an observatory by the current flowing through steel columns composing the TOKYO SKYTREE. This paper presents simulation results of lightning current distribution and magnetic fields around the observatory. Simulated results are from the finite-difference time-domain (FDTD) method which is one of the most widely used numerical electromagnetic analysis methods. The knowledge of these current distribution characteristics and magnetic fields would be very useful for lightning protection of TOKYO SKYTREE.

Structural Identification: Opportunities and Challenges

Civil engineeringmaster builders havebeen constructingmasterpieces for millennia, long before the recent advent of systems engineering. However, since the 1950s, the planning, financing, design, construction, operation, and maintenance of civil engineered constructed systems, e.g., buildings, bridges, airports, plants, tunnels, dams, antenna towers, storage tanks, power transmission towers, highways, railroads, and pipelines, became the elements of highly complex, intertwined, and interdependent systems in dense urban areas. Such highly complex and multidomain systems, termed infrastructures, include government, education, healthcare, transportation, water, communication, and energy [U.S. Department of Homeland Security (DHS) 2010]. As urban populations grew, demands for infrastructure services increased. Meanwhile, the engineered elements of infrastructures aged and deteriorated, and their operational and structural capacity started to fall short of the demands. Their fragility was recognized as the failure of one infrastructure element that precipitated cascading consequential failures of additional elements from different infrastructures. Failures of critical infrastructure because of natural or manufactured hazards reiterate this connectivity. For example, on January 2, 1998, “a century-oldwatermain ruptured under lower FifthAvenue in New York City, creating a car-swallowing, curb-to-curb sinkhole andwatery chaos in a bustling neighborhoodwhose streets resembled Venice for a few hours. Then, as the rivers receded, a gas main broke and the crater spewed forth a tower of orange flames. No one was injured . . . but water damaged scores of lobbies, storefronts, and basements for blocks around, 40 residents were evacuated, hundreds of offices and businesses were closed, subways were halted, traffic was rerouted, and gas, water, electric, steam heat, and telephone services were disrupted for many” (McFadden 1998). Three infamous 21st century examples further demonstrate the unexpected cascading consequences of infrastructure failure: • In the case of the World Trade Center collapse on September 11, 2001, while airplane impact was a design consideration for the Towers, the consequential explosion and fire associated with an airplane impact were neglected in the design. Catastrophic and disproportionate collapse of the Towers because of fire in the upper floorswas completely unexpected. TheNIST investigation (NIST 2005) into the collapses led to new code provisions. • In the city of New Orleans on August 31, 2005, the storm surge because of Hurricane Katrina caused more than 50 breaches in drainage canal levees and navigational canal levees and precipitated the worst engineering disaster in the history of the United States. Such an event had been expected, but neither the consequences nor the preparation needed for effective emergency response were properly estimated (ASCE 2007). • An hour after the March 11, 2011 Tohoku earthquake off the coast of Japan, the tsunami wave breached the protective walls at the Fukushima Nuclear Power Plant and destroyed backup diesel power systems, leading to partial meltdowns at several reactors. The diesel generators were situated in a low spot on the assumption that the tsunami walls were high enough to protect against any likely tsunami. Subsequently, ancient stone markers indicating higher tsunami events were reported (Associated Press 2011).

Happiness and the patterns of life: a study of geolocated tweets.

The patterns of life exhibited by large populations have been described and modeled both as a basic science exercise and for a range of applied goals such as reducing automotive congestion, improving disaster response, and even predicting the location of individuals. However, these studies have had limited access to conversation content, rendering changes in expression as a function of movement invisible. In addition, they typically use the communication between a mobile phone and its nearest antenna tower to infer position, limiting the spatial resolution of the data to the geographical region serviced by each cellphone tower. We use a collection of 37 million geolocated tweets to characterize the movement patterns of 180,000 individuals, taking advantage of several orders of magnitude of increased spatial accuracy relative to previous work. Employing the recently developed sentiment analysis instrument known as the hedonometer, we characterize changes in word usage as a function of movement, and find that expressed happiness increases logarithmically with distance from an individual's average location.