SECX1029 ANTENNAS and WAVE PROPAGATION UNIT IV PROPAGATION PREPARED by Ms.VALENTINA , Ms.MERLIN SHEEBA
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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. -
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. -
Beyond-Line-Of-Sight Communications with Ducting Layer Ergin Dinc, Student Member, IEEE, Ozgur B
IEEE COMMUNICATIONS MAGAZINE 1 Beyond-Line-of-Sight Communications with Ducting Layer Ergin Dinc, Student Member, IEEE, Ozgur B. Akan, Senior Member, IEEE Abstract—Near-surface wave propagation at microwave fre- 8 :JR:`R IQ ].V`V quencies especially 2 GHz and above shows significant depen- dence on atmospheric ducts that are the layer in which rapid decrease in the refractive index occurs. The propagating signals in the atmospheric ducts are trapped between the ducting layer and the sea surface, so that the power of the propagating signals do not spread isotropically through the atmosphere. As a result, these signals have low path-loss and can travel over-the-horizon. V: Since atmospheric ducts are nearly permanent at maritime and coastal environments, ducting layer communication is a promis- 8 IQ ].V`1H%H ing method for beyond-Line-of-Sight (b-LoS) communications especially in naval communications. To this end, we overview %H 1J$:7V` the characteristics and the channel modeling approaches for the ducting layer communications by outlining possible open research areas. In addition, we review the possible utilization of the ducting layer in Network Centric Operations (NCO) to empower decision making for the b-LoS operations. V: Index Terms—Atmospheric ducts, ducting layer, refractivity, beyond-line-of-sight communications Fig. 1. Signal spreading in the standard atmosphere and the atmospheric duct. I. INTRODUCTION TMOSPHERIC ducts that are caused by rapid decrease Ducting layer studies mainly focus on refractivity estimation A in the refractive index of the lower atmosphere have techniques and radar path-loss calculations [1], [2]. However, tremendous effects on the near-surface wave propagation. -
Spheric Duct Interference in TD-LTE Networks
Journal of Communications and Information Networks, Vol.2, No.1, Mar. 2017 DOI: 10.1007/s41650-017-0006-x Research paper c Posts & Telecom Press and Springer Singapore 2017 Special Issue on Wireless Big Data Analysis and prediction of 100 km-scale atmo- spheric duct interference in TD-LTE networks Ting Zhou1,3, Tianyu Sun1,2,3, Honglin Hu3*, Hui Xu1,3, Yang Yang1,3, Ilkka Harjula4, Yevgeni Koucheryavy5 1. Key Lab of Wireless Sensor Network and Communication, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, Shanghai 201800, China 2. School of Information Science and Technology, ShanghaiTech University, Shanghai 201204, China 3. Shanghai Research Center for Wireless Communication, Shanghai 201204, China 4. VTT Technical Research Centre of Finland, VTT FI-02044, Finland 5. Tampere University of Technology, Korkeakoulunkatu 10, Tampere FI-33720, Finland * Corresponding author, email: [email protected] Abstract: Atmospheric ducts are horizontal layers that occur under certain weather conditions in the lower atmosphere. Radio signals guided in atmospheric ducts tend to experience less attenuation and spread much farther, i.e, hundreds of kilometers. In a large-scale deployed TD-LTE (Time Division Long Term Evolution) network, atmospheric ducts cause faraway downlink wireless signals to propagate beyond the designed protection distance and interfere with local uplink signals, thus resulting in a large outage probability. In this paper, we analyze the characteristics of ADI atmospheric duct interference (Atmospheric Duct Interference) by the use of real network-side big data from the current operated TD-LTE network owned by China Mobile. The analysis results yield the time varying and directional characteristics of ADI. -
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 -
Ducting and Turbulence Effects on Radio-Wave Propagation in An
Progress In Electromagnetics Research B, Vol. 60, 301–315, 2014 Ducting and Turbulence Effects on Radio-Wave Propagation in an Atmospheric Boundary Layer Yung-Hsiang Chou and Jean-Fu Kiang* Abstract—The split-step Fourier (SSF) algorithm is applied to simulate the propagation of radio waves in an atmospheric duct. The refractive-index fluctuation in the ducts is assumed to follow a two- dimensional Kolmogorov power spectrum, which is derived from its three-dimensional counterpart via the Wiener-Khinchin theorem. The measured profiles of temperature, humidity and wind speed in the Gulf area on April 28, 1996, are used to derive the average refractive index and the scaling parameters in order to estimate the outer scale and the structure constant of turbulence in the atmospheric boundary layer (ABL). Simulation results show significant turbulence effects above sea in daytime, under stable conditions, which are attributed to the presence of atmospheric ducts. Weak turbulence effects are observed over lands in daytime, under unstable conditions, in which the high surface temperature prevents the formation of ducts. 1. INTRODUCTION There are three basic types of atmospheric duct: Surface duct, surface-based duct and elevated duct. A surface duct is usually caused by a temperature inversion [1]. An evaporation duct is a special case of surface duct, which appears over water bodies accompanied by a rapid decrease of humidity with altitude [2]. Surface-based ducts are formed when the upper air is exceptionally warm and dry compared with that on the surface [2]. Elevated ducts usually appear in the trade-wind regions between the mid-ocean high-pressure cells and the equator [2]. -
Geophysical Aspects of Atmospheric Refraction
NRL Report 7725 Geophysical Aspects of Atmospheric Refraction CHARLES G. PURVES Aerospace Systems Branch Space Systems Division June 7, 1974 NAVAL RESEARCH LABORATORY Washington, D.C. Approved for public release; distribution unlimited. C= SECURITY CLASSIFICATION OF THIS PAGE (When Data Entered) C-` READ INSTRUCTIONS r- REPORTDOCUMENTATION PAGE BEFORE COMPLETING FORM ;11 I. REPORT NUMBER 2, GOVT ACCESSIONNO. 3. RECIPIENT'S CATALOG NUMBER 11 NRL Report 7725 -7 4. TITLE (and Subtitle) S. TYPE OF REPORT & PERIOD COVERED Final report on one phase of a r1r GEOPHYSICAL ASPECTS OF ATMOSPHERIC continuing NRL Problem. REFRACTION 6. PERFORMING ORG. REPORT NUMBER 7, AUTHOR(s) S. CONTRACT OR GRANT NUMBER(s) Charles G. Purves 9. PERFORMINGORGANIZATION NAME AND ADDRESS 10. PROGRAMELEMENT, PROJECT, TASK AREA & WORK UNIT NUMBERS Naval Research Laboratory NRL Problem R07-20 Washington, D.C. 20375 RE 12-151-402-4024 II.CONTROLLING OFFICE NAME AND ADDRESS 12. REPORT DATE Department of the Navy June 7, 1974 Office of Naval Research 13. NUMBER OF PAGES Arlington, Va. 22217 44 14. MONITORING AGENCY NAME & ADDRESS(If different from Controlling Office) IS. SECURITY CLASS. (of this report) Unclassified ISa. DECLASSIFICATION/DOWNGRADING SCHEDULE 16. DISTRIBUTION STATEMENT (of this Report) Approved for public release; distribution unlimited. 17. DISTRIBUTION STATEMENT (of the abstract enteredin Block 20, if different from Report) 18. SUPPLEMENTARY NOTES 19. KEY WORDS(Continue on reverse side if necessary and identify by block number) Anomalous radar propagation Electromagnetic waves Ray tracing Cloud correlations Haze layers Refractive index forecasts Cloud mosaic Microwave refractometer Refractive index profiles Convective cloud cells Radar horizon Satellite cloud photography Ducting gradients Radios (Continued) 20. -
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. -
The Exam Corner #4
THE EXAM CORNER #4 By Steve Weeks, AA8SW This is the second in the series of three lessons on propagation. The General Class license is so desirable because it gives us access to worldwide communications on HF bands, but over-the-horizon signals have to be “bounced” (technically refracted) back down to Earth one or more times by the atmosphere (most often, by the ionosphere). Again, I will briefly discuss what you need to know about an aspect of that subject, then show you the only exam questions that could appear on that aspect, and follow with hints as to how you can remember the right answer. The correct answer is in bold. ● This unit focuses on two simple concepts – the Lowest Usable Frequency (LUF) and Maximum Usable Frequency (MUF), which are just what they sound like – between the LUF and the MUF are the frequencies that are usable for communications between two given points at a given time. Note, this is not a 24-hour average, it is as of the specific time that the communication is desired to be made. Below the LUF, radio waves are absorbed by the ionosphere and not “bounced” back. G3B07 What does LUF stand for? A. The Lowest Usable Frequency for communications between two points B. The Longest Universal Function for communications between two points C. The Lowest Usable Frequency during a 24 hour period D. The Longest Universal Function during a 24 hour period G3B08 What does MUF stand for? A. The Minimum Usable Frequency for communications between two points B. The Maximum Usable Frequency for communications between two points C.