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A Simplified Mathematical Model to Calculate the Maximum Usable Frequencies Over Iraqi Territory Khalid A
A Simplified Mathematical Model to Calculate the Maximum Usable Frequencies Over Iraqi Territory Khalid A. Hadi*, Loay E. Goerge** A Simplified Mathematical Model to Calculate the Maximum Usable Frequencies Over Iraqi Territory Khalid A. Hadi*, Loay E. Goerge** * Department of Astronomy & Space, College of Science, University of Baghdad ** Department of Computer Science, College of Science, University of Baghdad Receiving Date: 25-02-2011 - Accept Date: 13-06-2011 Abstract In this project, the spatial and temporal variation of maximum usable frequency (MUF) parameter is investigated and modeled. The values of MUF for Baghdad station links, with other stations distributed over Iraq territory, where determined using the international reference model (RECF533) for HF propagation. The determined MUF dataset reflected that the spatial distribution of this parameter for Baghdad station shows circular symmetry, which stimulated the possibility of using a two dimensional second order polynomial in order to describe MUF variation. The main feature of this adopted mathematical model is its low complexity. The results of conducted analysis indicated that the spatial variation of MUF is simple while its temporal variation is more complicated and needs more sophisticated mathematical description than the polynomial description. The test results showed that the accuracy of proposed simple model lies within the tolerance of REC533 reference model. Key words: Ionosphere, HF communication prediction, MUF Vol 7 No: 4, October 2011 1 20 ISSN: 2222-8373 A Simplified Mathematical Model to Calculate the Maximum Usable Frequencies Over Iraqi Territory 1. INTRODUCTION The Maximum Usable Frequency, denoted by MUF, is an important ionospheric parameter. It is defined as the highest frequency that allows reliable long-range high frequency (HF) radio communication between two points due to ion-ospheric refraction. -
Jet Streams Anomalies As Possible Short-Term Precursors Of
Research in Geophysics 2014; volume 4:4939 Jet streams anomalies as the existence of thermal fields, con nected with big linear structures and systems of crust Correspondence: Hong-Chun Wu, Institute of possible short-term precursors faults.2 Anomalous variations of latent heat Occupational Safety and Health, Safety of earthquakes with M 6.0 flow were observed for the 2003 M 7.6 Colima Department, Shijr City, Taipei, Taiwan. > (Mexico) earthquake.3 The atmospheric Tel. +886.2.22607600227 - Fax: +886.2.26607732. E-mail: [email protected] Hong-Chun Wu,1 Ivan N. Tikhonov2 effects of ionization are observed at the alti- 1Institute of Occupational Safety and tudes of top of the atmosphere (10-12 km). Key words: earthquake, epicenter, jet stream, pre- Health, Safety Department, Shijr City, Anomalous changes in outgoing longwave cursory anomaly. radiation were recorded at the height of 300 Taipei, Taiwan; 2Institute of Marine GPa before the 26 December 2004 M 9.0 Acknowledgments: the authors would like to Geology and Geophysics, FEB RAS; w express their most profound gratitude to the Indonesia earthquake.4 These anomalous ther- Yuzhno-Sakhalinsk, Russia National Center for Environmental Prediction of mal events occurred 4-20 days prior the earth- the USA and the National Earthquake quakes.5-8 Information Center on Earthquakes of the U.S. Local anomalous changes in the ionosphere Geological Survey for data on jet streams and 9-11 earthquakes on the Internet. Abstract over epicenters can precede earthquakes. Statistical analysis showed that these changes Dedications: the authors dedicate this work to occurred about 1-5 days before seismic the memory of Miss Cai Bi-Yu, who died in Satellite data of thermal images revealed events.12 To connect the listed above abnormal Taiwan during the 1999 earthquake with magni- the existence of thermal fields, connected with phenomena to preparation of earthquakes, tude M=7.3. -
Using High Frequency Propagation to Calculate Basic Maximum Usable Frequency
Using High Frequency Propagation to Calculate Basic Maximum Usable Frequency Israa Abdualqassim Mohammed Ali* * University of Baghdad, College of Science, Baghdad, Iraq Received: XX 20XX / Accepted: XX 20XX / Published online: ABSTRACT A comparison between observed (obs.) digital ionospheric sounding data and predicted (pre.) using International Reference Ionosphere (IRI) model for critical frequency (foF2) and Basic Maximum Usable Frequency (BMUF) of ionospheric F2-Layer has been made. A mid-latitude region selected for this research work by using data from station Wakkanai (45.38o N, 141.66o E). This study included 12 monthly median data from year (2001, R12=111) selected for high Sunspot number (SSN) and years for low SSN (2004, R12=44) and (2005, R12=29). Frequency parameters foF2 reveals that there is a good correlation between observed and predicted except for January of years 2001 and 2004, and BMUF revealed that there is a good correlation between observed and predicted for years of low SSN and all months except in month 1, 9 and 12 of year 2004, for year 2001 of high SSN there is a bad correlation. A correction factor as a function of time used from fitting technique to correct the predicted value with observed value of BMUF for year 2001. Keywords: Ionosphere; foF2; M3000F2; BMUF Author Correspondence, e-mail: [email protected] 1. INTRODUCTION The maximum usable frequency (MUF) is important ionospheric parameter for radio users because of its role in radio frequency management and for providing a good communication 1 link between two locations (Athieno et al., 2015; Suparta et al., 2018). -
Radio Transmission and the Ionosphere
Ih S. DEPARTMENT OF COMMERCE NATIONAL BUREAU OF STANDARDS WASHINGTON / » ruT O v / Letter Circular LC-614 RADIO TRANSMISSION AND THE IONOSPHERE October 23, 19^0 6 . s TKD :ANK U. 3. DEPARTMENT OF COMMERCE Letter 1-6 NATIONAL BUREAU OF STANDARDS Circular Washington LC-6l4 ( Supersedes LC-E75) October 23 , 19^0 RADIO TRANSMISSION' AND THE IONOSPHERE Radio transmission over great distances is made possible by . reflection of the radio waves from ionized (electrically conduct- ing) layers in the ionosphere, the upper region of the earth* atmosphere. How far the radio waves go, and what frequencies may be used, are determined by the heights and the degree of ionization of the ionized layers, which are located between about BO kilometers (30 miles) and 400 kilometers (250 miles) above the earth's surface. Because of variations in the ionized layers, the conditions of radio wave transmission vary with time of day, with season, and from year to year. For the efficient maintenance of radio services it is important to have a constant supply of information on these changes. To this end an ionosphere observing, reporting, and predicting service is provided by the National Bureau of Standards. It is analogous to the weather reporting service, though quite independent of it-; the factors producing or affecting weather exist at much lower levels of the atmosphere than the ionosphere. The results of the Bureau * work on the ionosphere arid -radio transmission are made available to the public by a Science Service Urslgram and radio broadcast each week, and regular publication each month and each quarter, as well as through special papers (see References at end hereof) published from time to time on particular phases of the subject. -
Radio Communications
RADIO COMMUNICATIONS An Amateur Radio Technician and General Class License Study Guide Prepared by John Nordlund – AD5FU and Edited by Lynette Dowdy - KD5QMD Based on the Element 2 Technician Exam Question Pool Valid from 7/1/06 until 7/1/2010 and the Element 3 General Exam Question Pool Valid 7/1/2007 until 7/1/2011 Page 1 of 78 Acknowledgment: My greatest thanks to Lynette – KD5QMD, for her understanding and assistance, without which this book would be filled with countless typographical and grammatical errors and an overload of confusing jargon and bewildering techno-babble. | | This publication is the intellectual property of the author, and may not be reproduced for commercial gain for any purpose without the express permission of the author. | | However, Share the Fun. | | This publication may be freely distributed for the educational benefit of any who would care to obtain or upgrade their amateur radio license. | | | If you love the hobby you have a duty of honor to pass it along to the next generation. | | | 73 de AD5FU Page 2 of 78 How to use this study guide. Contained within the next 73 pages is a text derived from the official exam question pools for Element 2 Technician and Element 3 General class exams. It is the expressed opinion of the author and editor of this study guide that studying the full question pool text is counterproductive in attempting to obtain your Amateur Radio License. We therefore do not recommend downloading the actual exam question pool texts. This study guide is divided into sections of related information. -
Cold Plasma Diagnostics in the Jovian System
341 COLD PLASMA DIAGNOSTICS IN THE JOVIAN SYSTEM: BRIEF SCIENTIFIC CASE AND INSTRUMENTATION OVERVIEW J.-E. Wahlund(1), L. G. Blomberg(2), M. Morooka(1), M. André(1), A.I. Eriksson(1), J.A. Cumnock(2,3), G.T. Marklund(2), P.-A. Lindqvist(2) (1)Swedish Institute of Space Physics, SE-751 21 Uppsala, Sweden, E-mail: [email protected], [email protected], mats.andré@irfu.se, [email protected] (2)Alfvén Laboratory, Royal Institute of Technology, SE-100 44 Stockholm, Sweden, E-mail: [email protected], [email protected], [email protected], per- [email protected] (3)also at Center for Space Sciences, University of Texas at Dallas, U.S.A. ABSTRACT times for their atmospheres are of the order of a few The Jovian magnetosphere equatorial region is filled days at most. These atmospheres can therefore rightly with cold dense plasma that in a broad sense co-rotate with its magnetic field. The volcanic moon Io, which be termed exospheres, and their corresponding ionized expels sodium, sulphur and oxygen containing species, parts can be termed exo-ionospheres. dominates as a source for this cold plasma. The three Observations indicate that the exospheres of the three icy Galilean moons (Callisto, Ganymede, and Europa) icy Galilean moons (Europa, Ganymede and Callisto) also contribute with water group and oxygen ions. are oxygen rich [1, 2]. Several authors have also All the Galilean moons have thin atmospheres with modelled these exospheres [3, 4, 5], and the oxygen was residence times of a few days at most. -
Moon–Magnetosphere Interactions: a Tutorial
Advances in Space Research 33 (2004) 2061–2077 www.elsevier.com/locate/asr Moon–magnetosphere interactions: a tutorial M.G. Kivelson a,b,* a University of California, Institute of Geophysics and Planetary Physics, UCLA, Los Angeles, CA 90095-1567, USA b Department of Earth and Space Sciences, UCLA, Los Angeles, CA 90095-1567, USA Received 8 May 2003; received in revised form 13 August 2003; accepted 18 August 2003 Abstract The interactions between the Galilean satellites and the plasma of the Jovian magnetosphere, acting on spatial scales from that of ion gyroradii to that of magnetohydrodynamics (MHD), change the plasma momentum, temperature, and phase space distribution functions and generate strong electrical currents. In the immediate vicinity of the moons, these currents are often highly structured, possibly because of varying ionospheric conductivity and possibly because of non-uniform pickup rates. Ion pickup changes the velocity space distribution of energetic particles, f (v), where v is velocity. Distributions become more anisotropic and can become unstable to wave generation. That there would be interesting plasma responses near Io was fully anticipated, but one of the surprises of Galileo’s mission was the range of effects observed at all of the Galilean satellites. Electron beams and an assortment of MHD and plasma waves develop in the regions around the moons, although each interaction region is different. Coupling of the plasma near the moons to the Jovian ionosphere creates auroral footprints and, in the case of Io, produces a leading trail in the ionosphere that extends almost half way around Jupiter. The energy source driving the auroral signatures is not fully understood but must require field aligned electric fields that accelerate elections at the feet of the flux tubes of Io and Europa, bodies that interact directly with the incident plasma, and at the foot of the flux tube of Ganymede, a body that is shielded from direct interaction with the background plasma by its magnetospheric cavity. -
The Magnetosphere-Ionosphere Observatory (MIO)
1 The Magnetosphere-Ionosphere Observatory (MIO) …a mission concept to answer the question “What Drives Auroral Arcs” ♥ Get inside the aurora in the magnetosphere ♥ Know you’re inside the aurora ♥ Measure critical gradients writeup by: Joe Borovsky Los Alamos National Laboratory [email protected] (505)667-8368 updated April 4, 2002 Abstract: The MIO mission concept involves a tight swarm of satellites in geosynchronous orbit that are magnetically connected to a ground-based observatory, with a satellite-based electron beam establishing the precise connection to the ionosphere. The aspect of this mission that enables it to solve the outstanding auroral problem is “being in the right place at the right time – and knowing it”. Each of the many auroral-arc-generator mechanisms that have been hypothesized has a characteristic gradient in the magnetosphere as its fingerprint. The MIO mission is focused on (1) getting inside the auroral generator in the magnetosphere, (2) knowing you are inside, and (3) measuring critical gradients inside the generator. The decisive gradient measurements are performed in the magnetosphere with satellite separations of 100’s of km. The magnetic footpoint of the swarm is marked in the ionosphere with an electron gun firing into the loss cone from one satellite. The beamspot is detected from the ground optically and/or by HF radar, and ground-based auroral imagers and radar provide the auroral context of the satellite swarm. With the satellites in geosynchronous orbit, a single ground observatory can spot the beam image and monitor the aurora, with full-time conjunctions between the satellites and the aurora. -
HF Radio Propagation
Introduction to HF Radio Propagation 1. The Ionosphere 1.1 The Regions of the Ionosphere In a region extending from a height of about 50 km to over 500 km, most of the molecules of the atmosphere are ionised by radiation from the Sun. This region is called the ionosphere (see Figure 1.1). Ionisation is the process in which electrons, which are negatively charged, are removed from neutral atoms or molecules to leave positively charged ions and free electrons. It is the ions that give their name to the ionosphere, but it is the much lighter and more freely moving electrons which are important in terms of HF (high frequency) radio propagation. The free electrons in the ionosphere cause HF radio waves to be refracted (bent) and eventually reflected back to earth. The greater the density of electrons, the higher the frequencies that can be reflected. During the day there may be four regions present called the D, E, F1 and F2 regions. Their approximate height ranges are: • D region 50 to 90 km; • E region 90 to 140 km; • F1 region 140 to 210 km; • F2 region over 210 km. At certain times during the solar cycle the F1 region may not be distinct from the F2 region with the two merging to form an F region. At night the D, E and F1 regions become very much depleted of free electrons, leaving only the F2 region available for communications. Only the E, F1 and F2 regions refract HF waves. The D region is very important though, because while it does not refract HF radio waves, it does absorb or attenuate them (see Section 1.5). -
Comparison of Maximum Usable Frequency (MUF) Variability Over Peninsular Malaysia with IRI Model During the Rise of Solar Cycle 24
Journal of Atmospheric and Solar-Terrestrial Physics 138-139 (2016) 87–92 Contents lists available at ScienceDirect Journal of Atmospheric and Solar-Terrestrial Physics journal homepage: www.elsevier.com/locate/jastp Research paper Comparison of maximum usable frequency (MUF) variability over Peninsular Malaysia with IRI model during the rise of solar cycle 24 R.A. Malik a,b,n, M. Abdullah a,c, S. Abdullah c, M.J. Homam d a Department of Electrical, Electronic and Systems Engineering, Universiti Kebangsaan Malaysia, Malaysia b Science & Technology Research Institute for Defence (STRIDE), Malaysia c Space Science Centre (ANGKASA), Universiti Kebangsaan Malaysia, Malaysia d Universiti Tun Hussein Onn Malaysia, Malaysia article info abstract Article history: The aim of this paper is to study maximum usable frequency (MUF) variability over Peninsular Malaysia Received 27 July 2015 (112.5°E, 2.5°N) which is located in the equatorial region during the rise of Solar Cycle 24 (2009–2011). Received in revised form The MUF Test data was obtained from high frequency (HF) transmission tests that were conducted from 16 December 2015 April 2009 to September 2011. Relative variability VR was used to compute the relative variability of MUF. Accepted 26 December 2015 Variability of diurnal, seasonal and sunspot effect on MUF of test was compared to International Re- Available online 29 December 2015 ference Ionosphere (IRI) version of 2012. The results show that: (a) MUF from the IRI model is higher Keywords: than the MUF Test but the magnitude for the -
Radio Sounding of the Venusian Atmosphere and Ionosphere with Envision
EPSC Abstracts Vol. 13, EPSC-DPS2019-609-1, 2019 EPSC-DPS Joint Meeting 2019 c Author(s) 2019. CC Attribution 4.0 license. Radio Sounding of the Venusian Atmosphere and Ionosphere with EnVision Silvia Tellmann (1), Yohai Kaspi (2), Sébastien Lebonnois (3) , Franck Lefèvre (4), Janusz Oschlisniok (1), Paul Withers (5), Caroline Dumoulin (6), and Pascal Rosenblatt (6,7) (1) Rheinisches Institut für Umweltforschung, Abteilung Planetenforschung, Universität zu Köln, Cologne, Germany, (2) Department of Earth and Planetary Sciences, Weizmann Institute of Science, Rehovot, Israel, (3) LMD/IPSL, Sorbonne Université, CNRS, Paris, France, (4) LATMOS, CNRS/Sorbonne Université, Paris,(5) Astronomy Department, Boston University, Boston, MA, USA, (6) Laboratoire de Planétologie et Géodynamique, Université de Nantes, France, (7) Geoazur, Nice Sophia-Antipolis University, France, ([email protected]) Abstract temperature and pressure profiles in the mesosphere and upper troposphere of Venus (~ 40 - 90 km). The EnVision is a one of the final candidates for the M5 first radio occultation experiment at Venus was call of the Cosmic Vision program from ESA. It is conducted during the Mariner 5 flyby in 1967 [2], dedicated to unravel some of the numerous open followed by Mariner 10 [3], several Venera missions questions about Venus' past, current state and future. [4], Magellan [5] and the Pioneer Venus Orbiter [6], The Radio Science Experiment on EnVision will and Akatsuki [7]. The most extensive radio perform extensive studies of the gravitational field occultation study of the Venus atmosphere so far was but also Radio Occultations to sense the Venus carried out by the VeRa experiment on Venus atmosphere and ionosphere at a high vertical Express [8,9]. -
The Ohm Town News
THE OHM TOWN NEWS Voice of the Bridgerland Amateur Radio Club >>>>>>>> http://www.barconline.org <<<<<<<< MarchMarch 20201010 Some Contents… Presidents Message ................................ 2 Ham Profile: Kevin Reeve (N7RXE) .......... 3 2010 Club Budget Voting Form .............. 4 Upcoming Activities ................................ 5 D-Star update information .................... 6 ARRL newsletter information ................. 8-11 Test Questions for Extra Class License ... 12 PRESIDENT’S MESSAGE For the past several years, we have been at the bottom of one of the lowest solar activity cy- cles in history. But it looks like solar cycle 24 is starting its upward trend. The past 10 weeks have seen only three days with no sunspots. The prediction is that solar cycle 24 will peak in mid 2013. In other words, at the peak of the cycle you can basically make contact with other amateur radio operators all over the world. On the other hand, when the sunspot activity is in the low part of the cycle (like it is now) radio signals don't normally travel very far -- but some- times they do and that uncertainty is one of the many things that make the hobby fun. Any form of radio communications that uses the High Frequency (HF) bands and iono- spheric radio propagation is very dependent upon the state of the ionosphere. The higher the levels of radiation received from the Sun, the greater the levels of ionization in the ionosphere and in general this brings better propagation conditions for HF radio communications. The importance of the ionosphere lies in its ability to reflect some radio waves back to earth under certain conditions.