Near Vertical Incidence Skywave is also called NVIS. This page is intended as a repository of NVIS related links and info for my own use, and eventually documentation of any NVIS efforts I undertake.Technical DataNVIS works on bands from 1.8MHz (160 meter) to about 14MHz (20 meter); the most active amateur bands for NVIS operations are on 3.5MHz (80m) and 7MHz (40m), with some use on 5MHz (60m). Since NVIS works by radiating signal nearly vertical, and bouncing it off of the ionosphere. Higher frequencies result in too much absorption, and the signals are not refracted back down towards earth. The effect of NVIS is to allow radio comms beyond LOS (what higher frequencies use), but also inside of effective minimum skywave distances. This is especially useful in mountainous areas where LOS distance is dramatically reduced by terrain obstructions, but it has applications in other areas as well.Required Equipment
- HF Radio - 40m and 80m capability
- 1/4 wavelength wire antenna (33ft for 40m, 66ft for 80m; could "tie on" the 2nd 33ft...)
- Car acts as other half of the "dipole". Alternatively, could use another 1/4 wavelength wire laid along the ground ("counterpoise").
MiscSome links to good information: