Amateur radio experiments
Near Vertical Incidence Sky-Wave
NVIS is a propagation mode which uses high angle radiation to send signals almost straight up to be reflected back to Earth for very effective short to medium distance communications and used by the military to make it hard to detect the location of the signal, you may have seen curved antenna mounting on landrovers and jeeps and wandered why??
Near Vertical Incidence Sky-wave (NVIS)
The propagation mode that uses the ionosphere as a parabolic reflector to increase local communications on HF to 200 – 300 miles.
Ideal for emergency communications a good way to use of NVIS antennas and propagation.
A great video of this very well explained below…