Near Vertical incidence Skywave Propagation NVIS Antennas - Ham Radio Q&A. Post 1909.
If you can't see the video, please insert this title URL into your browser search box: https://www.youtube.com/watch?v=fvZ7z-6wAy0. If you need a simple, efficient HF antenna for local, regional, and state coverage, why not build a NVIS (near vertical incidence skywave) antenna? These antennas are designed to put out a strong signal covering 100 to 300 miles/162 to 486 kilometers from your station. Such antennas can serve as valuable backups to regular VHF/UHF coverage, especially when repeaters are down. In this video, Michael Martens (KB9VBR) show us how to build a simple NVIS antenna. These antennas are perfect for local nets and regional coverage. Although there is no "fast and sure" rule for how much the antenna should be above ground, I've found a 40 meter dipole about 15-feet/4.57 meters above ground and an 80 meter dipole about 31-feet/9.45 meters above ground will generate a good signal for about 300 miles/162 kilometers on most days. Michael do