One of the best NVIS primers I’ve encountered.
http://kv5r.com/ham-radio/nvis-antennas/
Near-Vertical Incident Skywave is a combination of radio hardware, skywave radio propagation, operating procedures, cooperation, and knowledge used by a group of radio operators who need reliable regional communications. It fills the gap between line-of-sight groundwave and long-distance “skip” skywave communications.
echo delta sierra 