A5074590255- Radio Wave Propagation Studies
- Ionosphere and magnetosphere dynamics
- GNSS positioning and interference
- Satellite Communication Systems
- Power Line Communications and Noise
- Radio Astronomy Observations and Technology
- Antenna Design and Analysis
- Earthquake Detection and Analysis
- Millimeter-Wave Propagation and Modeling
- Electromagnetic Compatibility and Measurements
- Antenna Design and Optimization
- Telecommunications and Broadcasting Technologies
- Solar and Space Plasma Dynamics
- Energy Harvesting in Wireless Networks
- Disaster Management and Resilience
- Lightning and Electromagnetic Phenomena
- Magnetic confinement fusion research
- IPv6, Mobility, Handover, Networks, Security
- Innovative Approaches in Technology and Social Development
- Space exploration and regulation
- Precipitation Measurement and Analysis
- Peatlands and Wetlands Ecology
- Electromagnetic Compatibility and Noise Suppression
- Geomagnetism and Paleomagnetism Studies
- Historical Geography and Cartography
University of Twente
2014-2024
Ministry of Economic Affairs and Climate Policy
2023-2024
Radiocommunications Agency
2005-2020
Mercu Buana University
2020
Aalto University
2020
Fukui Prefectural University
2020
Kumamoto University
2020
Telkom University
2020
University of Bath
2018-2019
Near Vertical Incidence Skywave (NVIS) communication uses the ionosphere as a reflector to cover continuous area with radius of at least 150 km around transmitter, on frequencies typically between 3 and 10 MHz. In developing countries, in areas lacking any other telecommunication infrastructure, it is used daily basis for voice data communication. It may also be ad-hoc emergency (disaster) regions. This paper proposes optimum heights above ground horizontal dipole antennas NVIS, based...
Near Vertical Incidence Skywave propagation can provide High Frequency (HF: 3-30 MHz) radio coverage in an area of 300 by km without the need for any intermediate infrastructure. It is therefore very well suited disaster relief communication. However, electromagnetic waves refracted ionosphere are prone to fading caused multipath and polarization change ionosphere. Historically, different diversity reception systems have been devised reduce this fading. By contrast, modern HF Multiple Input...
Abstract The ionized upper portion of the atmosphere, ionosphere, affects radio signals traveling between satellites and ground. This degrades performance satellite navigation, surveillance, communication systems. Techniques to measure mitigate ionospheric effects in particular total electron content (TEC) are therefore required. TEC is usually determined by analyzing differential delay experienced dual‐frequency signals. Here we demonstrate a technique which enables be derived using...
Separate excitation of the characteristic waves in ionosphere results two orthogonal propagation channels on same frequency, which may be used diversity and multiple-input, multiple-output (MIMO) systems. In this article, a method to measure isolation between these paths is proposed demonstrated near vertical incidence skywave (NVIS) experiment at frequency 7 MHz over 105-km distance. Characteristic wave exceeding 25 dB measured during "Happy Hour": interval when path just opens or closes...
In the E-region of ionosphere, at heights between 90 and 130 km, thin patches enhanced ionization occur intermittently. The electron density in these sporadic-E (Es) clouds can sometimes be so high that radio waves with frequencies up to 150 MHz are obliquely reflected. While this phenomenon is well known, reflection mechanism itself not understood. To investigate question, an experimental system has been developed for accurate polarimetric fading measurements 50 reflected by mid-latitude Es...
Observation of the 3-dimensional (3-D) electron density ionosphere is useful to study large-scale physical processes in space weather events. Ionospheric data assimilation and ionospheric tomography are methods that can create an image 3-D distribution. While multiple techniques have been developed over past 30 years, there relatively few studies show accuracy algorithms. This paper outlines a novel simulation approach test quality tomographic inversion. The uses observations from incoherent...
Systems for atmospheric research and wireless communication use the High Frequency (HF) radio spectrum. At these frequencies, typically up to 20 MHz, ambient electromagnetic noise is stronger than generated by receiver itself, thereby limiting sensitivity of instruments. Especially in urban areas, level high. In remote rural environments, where artificial sources are absent, a much lower observed. It has been shown that this arrives via ionospheric propagation consists impulsive from...
An extensive propagation measurement survey was performed between The Netherlands and the United Kingdom. Seven mixed land/sea paths were monitored simultaneously, with path lengths ranging from 55 to 370 km. Eight frequencies 500 700 MHz used. Over 21 million measurements collected during days. This paper describes actions taken assure high data quality. Detailed results are provided can be used as model test vectors. These compared predictions of ITU-R Rec. P.1546-4 model. disappointing:...
An experiment to investigate several characteristics of near vertical incidence skywave (NVIS) propagation (polarization, characteristic waves and their isolation, elevation angles, radio noise) over a distance 105 km at 7 MHz was performed in The Netherlands. Daytime wave with almost perfectly circular polarization high isolation values had been expected from our earlier work could now be demonstrated. Simultaneous angle measurements showed pure single-hop F2-layer reflection no ground...
The design, realization, and measurement results of a high-accuracy multiyear 3.5 GHz trans-horizon radio propagation system are discussed, with both emphasis on the implemented technical measures to enhance accuracy overall reliability measurements. measurements have been performed two different paths 253 234 km length, using transmitters one receiver in period September 2013 till November 2016. One travels over wetland; other path can be considered as land path. On each path, an additional...
This paper investigates 7 MHz ionospheric radio wave propagation between pairs of distant countries that simultaneously lie on the terminator. is known as greyline propagation. Observations amateur beacon transmitters recorded in Weak Signal Propagation Reporter (WSPR) database are used to investigate times day signals were observed during year 2017. The WSPR network consists thousands automated and observers distributed over globe. a very useful resource for science it offers date time at...
In HF (3-30 MHz) communications the ambient electromagnetic background noise or `radio noise' generally is limiting factor in reception. Radio measurements are needed for spectrum pollution control and to provide reference levels radio system design. This article discusses influence of measurement antenna on results. A novel method compare polarization hemisphere coverage antennas proposed. used three antennas. omni-directional introduced which has improved sensitivity high angle skywave...
For empirical research on Near Vertical Incidence Skywave (NVIS) characteristic wave propagation, a beacon transmitter system is needed that can be programmed to emit precisely defined elliptically and circularly polarized waves at high elevation angles. This paper proposes novel hybrid antenna-transmitter system, combination of synchronous dual channel turnstile antenna. The polarization emitted by the antenna power ratio phase difference outputs transmitter. Operating frequency between 3...
The amateur radio community is a global, highly engaged, and technical with an intense interest in space weather, its underlying physics, how it impacts communications. large-scale observational capabilities of distributed instrumentation fielded by operators science enthusiasts offers tremendous opportunity to advance the fields heliophysics, science, weather. Well-established networks like RBN, WSPRNet, PSKReporter already provide rich, ever-growing, long-term data bottomside ionospheric...
This article describes the design and validation of deployable low-power probes sensors to investigate influence ionosphere Earth's magnetic field on radio wave propagation below plasma frequency ionosphere, known as Near Vertical Incidence Skywave (NVIS) propagation. The waves that are bent downward by is dominated a bi-refractive mechanism called 'magneto-ionic propagation'. polarization both depends spatial angle between direction wave. described in this needed simultaneously signal...
and verification of the antenna patterns of broadcasting stations. Although it is intended for governmental institutions broadcasters may be also interest to anyone who wants evaluate large radiating structures. An airborne measurement to investigate properties structure in all dimensions needed. For complicated large transmitting arrays like multi-pattern VHF FM transmitters accuracy offered with an airborne measurement much higher than any other type of “inspection”.
During Hurricane Katrine in New Orleans 2005, the failure of telecommunication systems was a disaster by itself, creating chaos and seriously hampering mitigation measures during directly after event. Half telecom towers destroyed heavy wind, electrical grid an area as large The Netherlands Belgium combined flooded. rest ceased operation 48 hours later, when their backup power depleted. In some parts water stood 4.5 meters high, debris making roads impassable, blocking emergency repairs....