Understanding NVIS

The near vertical incidence skywave (NVIS) is an HF propagation mode where signals are transmitted towards, and returned from, the ionosphere almost vertically in order to provide local or regional coverage. This mode is also used in environments that are challenging for traditional HF propagation modes, such as in mountainous regions. This white paper provides a brief overview of HF and more common HF propagation modes, and discusses the underlying technical principles of NVIS, the different types of antennas for NVIS operation, and the operational aspects of NVIS. Download the paper for more information.