NVIS Refresher (RB371-372)
This summary is based upon the assumption that the reader has some familiarity with the subject of Near Vertical Incidence Skywave HF-SSB propagation for communications between 1.8 and around 10 Megahertz. NVIS is essential to anyone requiring reliable HF communication from one to 400 miles. Such users include the RACES, Operation SECURE, the Civil Air Patrol, FEMA, the U.S. Forest Service, MARS and others. This information is not found in conventional technical publications and (least of all) in the field of Amateur Radio. Having said that, here again are the highlights of NVIS (pronounced "niviss").
CA State OES began the Bulletins in the early 1950's to assist agencies and radio operators to become more familiar with RACES. They were issued periodically until 1985, at which time they began to be issued weekly over voice and digital radio systems of Amateur Radio and in print. Originally intended for California, increased demand, and a 1988 request by the ARRL for national distribution, led to their eventual worldwide distribution.