Download Free Elf Vlf Lf Propagation And System Design Book in PDF and EPUB Free Download. You can read online Elf Vlf Lf Propagation And System Design and write the review.

The effects of propagation conditions in the ELF/VLF/LF frequency band on the design and performance of digital communications systems are described in this report. Also, discussed in this report is the communications channel from a ground-based or airborne transmitting antenna through the earth- ionosphere waveguide to the receiver. Questions about coverage, noise, dispersion, time variance, and propagation disturbances are also summarized here. Keywords include: VLF Propagation, LF Minimum shift keying, ELF TACAMO, Dispersion, and Earth-ionosphere waveguide.
This publication reports the papers presented to a specialists' meeting held by the Electromagnetic Wave Propagation Panel at its Fall 1992 meeting. The topics covered on the occasion of that symposium include: Propagation aspects; Numerical modelling; Propagation measurements; and Propagation in sea water. Radio noise and interference; Long wave TE/TM Noise prediction model; Measurements; and ELF generated by auroral electrojet modulation. Antenna considerations; Antenna fundamentals; Scale modelling; Measurements of pattern and bandwidth; and Tethered aerostat VLF/LF transmitting antennas. System aspects; Viability assessment for reliable LW communication links. Future satellite systems; Orbiting system for ELF/VLF strategic communications, and Tethered satellite systems ... Electromagnetic propagation, Tethered ground based and satellite systems, Radio noise and interference, Reliability of LW communication links, Antenna considerations.
Based on the author's PhD thesis, this book is a theoretical study of subterranean radio communication, with the focus on methods that depend primarily on the penetration of electromagnetic fields through the ground. Through-the-earth communication using e-m fields - specifically magnetic induction - plays a role in search and rescue systems used in the mining industry. It is also used for borehole telemetry, pipeline location and by cavers and pot-holers. Chapters describe propagation, antennas, and the design of transmitters and receivers. A figure of merit - the specific aperture - is introduced as an aid to antenna design. A crucial aspect of all systems is the signal to noise ratio, for which the strategy of noise-matching is introduced. The design of a wide-band low-frequency sounder is described, for channel evaluation using a non-ideal binary sequence. A method of calculating the inverse of a generalised sequence is described, for which cross-correlation results in a system identification signal.

AGARD Index of Publications

Organisation du traité de l'Atlantique Nord. Groupe consultatif pour la recherche et le développement aérospatial. Technical Information Panel

Published: 1995

Total Pages: 508


Get eBook