RTNVIS

Type: Product

As of November 2026, RTNVIS has been mentioned in one podcast episode on Half as Interesting (Nov 2025). RTNVIS is a key component of FEMA's communication system, ensuring reliable communication during disasters.

Near vertical incidence skywave, or NVIS, is a skywave radio-wave propagation path that provides usable signals in the medium distances range — usually 0–650 km. It is used for military and paramilitary communications, broadcasting, especially in the tropics, and by radio amateurs for nearby contacts circumventing line-of-sight barriers. The radio waves travel near-vertically upwards into the ionosphere, where they are refracted back down and can be received within a circular region up to 650 km