What is the maximum effective range of NVIS?

The correct answer indicates that the maximum effective range of Near Vertical Incidence Skywave (NVIS) communication is approximately 300 miles. NVIS is a technique used in high frequency (HF) communications, where radio waves are transmitted at near-vertical angles. This allows for the signals to reflect off the ionosphere and return to the Earth in a relatively short range, making it particularly effective for communicating over distances typically within a few hundred miles.

In practical terms, NVIS is especially valuable for tactical operations, as it enables reliable communication in areas where line-of-sight propagation is not possible due to obstacles or the curvature of the Earth. By focusing energy vertically, NVIS creates less multipath distortion, which can adversely affect communications, and this allows for clearer signals over these shorter distances.

Understanding this effective range of about 300 miles helps operators choose NVIS as a suitable option for specific communication needs, such as field operations within that range, ensuring they can establish reliable contact.