David Gibson (Chief Executive of the Association of Building Engineers)
Based on the authors 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...
Based on the authors PhD thesis, this book is a theoretical study of subterranean radio communication, with the focus on methods that depend primarily...
David Gibson (Chief Executive of the Association of Building Engineers)
When Paul and Silas taught the gospel in Thessalonica, they were accused of having "turned the world upside down" (Acts 17:6, KJV). In reality, sin has turned our world upside down, and only the power of the gospel can turn it right-side up again. As Christians, we are constantly faced with teachings, policies, and behaviors that clearly contradict God's Word; even from within the church. Through spiritual training and discernment, we recognize that God has it right, and the world is subverting the message. David Gibson skillfully stacks the upside-down lies of the world against God's truth...
When Paul and Silas taught the gospel in Thessalonica, they were accused of having "turned the world upside down" (Acts 17:6, KJV). In reality, sin ha...
