An Eight-element SBF Fan-beam Array


Book Description

Eight short backfire (SBF) elements aligned on a common planar reflector form a highly efficient fan-beam array capable of yielding a maximum gain of approximately 24 dB. The influence of parameter variations on the array patterns and directivity was experimentally determined by varying the frequency. Normalized design parameters for highest efficiency and for circular polarization capability are tabulated. All array dimensions are given in wavelengths so that each application can easily be scaled for any desired frequency.




An SBF Array for Reception of Atmospheric Noise


Book Description

A four-element short-backfire array was designed, fabricated, and experimentally tested for use as a receiving antenna of low level atmospheric noise at 920 MHz. A complete set of design dimensions is presented as well as the resultant radiation patterns and frequency curves of sidelobe levels, half-power beamwidths, and input impedance. The effects of variations on the size and shape of the main reflector are discussed, especially when efficient operation with low sidelobes or high gain is of prime importance. Supporting data and tables of optimum design dimension are also provided for future VHF or UHF antenna applications in the gain range of 17 to 20 dB.




Instrumentation Papers


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Report on Research at AFCRL.


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Global Satellite Meteorological Observation (GSMO) Theory


Book Description

This book presents the principal structure of space systems, functionality, media and applications for modern remote sensing, transmission systems, meteorological antennas, propagation meteorological observation and transferring weather data from satellite to the ground infrastructures and users. The book starts with a short background to the development of Radio and Space systems including overview, concepts and applications of satellite communications in function of transfer meteorological observation data and images. It goes on to discuss the fundamental principles of the space platforms and orbital parameters, lows of satellite motions, new types of launching systems, satellite orbits and geometric relations, spacecraft configuration, payload structure, type of onboard antenna systems, satellite orbits and components of satellite bus. The author also provides comprehensive coverage of baseband and transmission systems, fundamentals of atmospheric electromagnetic radiation, satellite meteorological parameters and instruments, and research and applications in antenna systems and propagation. This is a companion book of Global Satellite Meteorological Observation Applications (Springer).




Global Mobile Satellite Communications


Book Description

Global mobile satellite communications (GMSC) are specific satellite communication systems for maritime, land and aeronautical applications. It enables connections between moving objects such as ships, vehicles and aircrafts, and telecommunications subscribers through the medium of communications satellites, ground earth stations, PTT or other landline telecommunications providers. Mobile satellite communications and technology have been in use for over two decades. Its initial application is aimed at the maritime market for commercial and distress applications. In recent years, new developments and initiatives have resulted in land and aeronautical applications and the introduction of new satellite constellations in non-geostationary orbits such as Little and Big LEO configurations and hybrid satellite constellations as Ellipso Borealis and Concordia system. This book is important for modern shipping, truck, train and aeronautical societies because GMSC in the present millennium provides more effective business and trade, with emphasis on safety and commercial communications. Global Mobile Satellite Communications is written to make bridges between potential readers and current GMSC trends, mobile system concepts and network architecture using a simple mode of style with understandable technical information, characteristics, graphicons, illustrations and mathematics equations. Global Mobile Satellite Communications represents telecommunications technique and technology, which can be useful for all technical staff on vessels at sea and rivers, on all types of land vehicles, on planes, on off shore constructions and for everyone possessing satellite communications handset phones.










The Disappearing Spoon


Book Description

From New York Times bestselling author Sam Kean comes incredible stories of science, history, finance, mythology, the arts, medicine, and more, as told by the Periodic Table. Why did Gandhi hate iodine (I, 53)? How did radium (Ra, 88) nearly ruin Marie Curie's reputation? And why is gallium (Ga, 31) the go-to element for laboratory pranksters? The Periodic Table is a crowning scientific achievement, but it's also a treasure trove of adventure, betrayal, and obsession. These fascinating tales follow every element on the table as they play out their parts in human history, and in the lives of the (frequently) mad scientists who discovered them. The Disappearing Spoon masterfully fuses science with the classic lore of invention, investigation, and discovery -- from the Big Bang through the end of time. Though solid at room temperature, gallium is a moldable metal that melts at 84 degrees Fahrenheit. A classic science prank is to mold gallium spoons, serve them with tea, and watch guests recoil as their utensils disappear.