Near Vertical Incident Skywave (NVIS) Antenna The goal of most high frequency (HF) operators is the communicate with stations as far away from where they are as possible. In an emergency this goal is not as helpful as communication locally and regionally. The Near Vertical Incident Skywave (NVIS) antenna, properly set-up and tuned, can provide reliable communications for about a 300 miles radius from where it is set up. NVIS does this by aimming the signal straight up, as opposed to a low angle. The NVIS' signal bounces back from the ionsphere, sometimes called "cloudwarming," and covers the local and regional area. NVIS solves a problem of communication with stations too far away from ground wave propogation and too close for skip communications. NVIS is an important emergency antenna.
A technical overview article. A more user friendly overview. A straight-to-the-point NVIS construction article. A comprehensive NVIS technical article with links. 40M-80M antenna in a case. Military NVIS. Determining the proper height for the NVIS antenna. |