Thanks to a terrific FAMPARC Club Member Stanley VK3BOT for introducing this very informative web site.. please take the time to look around..
The NCDXF, in cooperation with the IARU, constructed and operates a worldwide network of high-frequency radio beacons on 14.100, 18.110, 21.150, 24.930, and 28.200 megaHertz. These beacons help both amateur and commercial high-frequency radio users assess the current condition of the ionosphere. The entire system is designed, built and operated by volunteers at no cost except for the actual price of hardware components, shipping costs, and so on.
The first beacon began transmissions from Northern California in 1979 and was so successful that the IARU proposed a world wide network of beacons operating 24 hours a day. Over the next few years the network was expanded slowly. The current system of 18 beacons began operation in 1995 and has been in continuous operation ever since. Read More...
Three articles about the beacons appeared in QST and are reproduced by permission of the ARRL. These articles have a lot of interesting details about the background and history of the beacons.