Analysis of Air-ground Radio Wave Propagation Measurements at 800 MHz [by] G.D. Gierhart ... [et Al.]. PDF Download

Author: Institute for Telecommunication Sciences
Publisher:
ISBN:
Category : Radio measurements
Languages : en
Pages : 112

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Author: Gary D. Gierhart
Publisher:
ISBN:
Category : Radio measurements
Languages : en
Pages : 101

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Author: A. P. Barsis
Publisher:
ISBN:
Category : Radio measurements
Languages : en
Pages : 140

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In this report, descriptive and statistical analyses of radio propagation data over irregular terrain in approximately the 100- to 10,000 -MHz frequency range are presented, with special emphasis on communications between low antennas in the 225- to 400- MHz band. Data are evaluated in terms of medians and ranges of basic transmission loss, height gain, frequency dependence and effects of vegetation. Graphs provide first estimates of these parameters for specific applications in many terrain types. The results also provide information for verification and improvement of previously developed more general propagation model.

Author: Artem Saakian
Publisher: Artech House
ISBN: 1630818453
Category : Technology & Engineering
Languages : en
Pages : 422

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This completely updated second edition of an Artech House classic provides a thorough introduction to the basic principles of electromagnetic wave propagation of radio frequencies in real-world conditions, fully updated by including new achievements in theory and technology. It serves as an invaluable daily reference for practitioners in the field and as a complete, organized text on the subject. This comprehensive resource covers a wide range of essential topics, from the classification of radio waves, electromagnetic wave theory, and antennas for RF radio links, to the impact of the earth surface on the propagation of ground waves, atmospheric affects in radio wave propagation, and radio wave reception. The book explores the propagation of the ground radio waves, namely the waves that propagate in vicinity of the earth's surface (e.g., guided by that interface), without involvement of any atmospheric effects. Specifics of the high-frequency (HF) radio propagation due to reflections from ionospheric layers is studied, based on commonly used models of the ionospheric vertical profiles. Scattering of the radio waves of UHF and higher frequency bands from the random variations of the tropospheric refraction index (from tiny air turbulences) are also considered by using the principles of statistical radio-physics. Analysis of propagation conditions on real propagation paths, including analysis of the power budget of the VHF/UHF link to assure its stability (percentage of availability within observation time frame), terrestrial, broadcast, mobile, and satellite RF links are presented. The engineering design of the cellular networks, including LTE 4G, 5G and upcoming higher generations is explored. HF propagation predictions for extremely long-range links design for commercial and military applications are explained. Packed with examples and problems, this book provides a theoretical background for astrophysical, aeronomy and geophysical instrumentation design.

Author: Alfred E. Reilly
Publisher:
ISBN:
Category : Ionospheric radio wave propagation
Languages : en
Pages : 108

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The Chapman-Davies-Littlewood technique for the computation of the equivalent path of an ionospherically propagated High Frequency (HF) radio signal was used to determine the most probable modes of oblique propagation and the corresponding frequency windows that existed during six experimental aircraft flights in the polar region. In comparison to these results, the Elkins-Rush HF Polar Predictive Model has been found to be inadequate for short-term propagation predictions. These oblique propagation measurements have verified Feldstein and Starkov's conclusion that the magnetic Index Q is a good indicator of the position, shape, and size of the Instantaneous Auroral Oval as they have defined it on the basis of ground-based optical measurements which they subjected to statistical analyses. An approach has been developed which sheds new light on the behavior of HF signals propagating via the polar ionosphere. On the basis of the results achieved using this approach, it is recommended that an attempt be made to develop a new method of predicting short-term polar region HF propagation conditions well in advance (that is, an hour or more in advance in real time). A hypothetical example of an application of such a method is given. Action should be taken soon to exploit this possibility. Additional work could extend the applicability of this approach beyond anything that has seemed feasible before. New understanding of the physics of the polar ionosphere could result. It is hoped that this report will stimulate the experimental and theoretical research that will result in this increased understanding of the polar ionosphere. (Author).

Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 112

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Author:
Publisher:
ISBN:
Category : Government reports announcements & index
Languages : en
Pages : 882

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Author: George Allen Hufford
Publisher:
ISBN:
Category : Radio
Languages : en
Pages : 80

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Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 726

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Author:
Publisher:
ISBN:
Category : Government publications
Languages : en
Pages : 978

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