#2. To: StraitGate, Esso, NeoconsNailed, Anthem, TommyTheMad, Artist, Lod, Ada (#1)
Studied them years ago. They are ionic heaters.. By heating the ionosphere, you can make it expand and go higher up. Then you can bounce signals off to military planes and ships from that higher altitude.
Some think that they can be used at certain cycles persecond to entrain the human mind and to make soldiers frightened. Some think George W Bush used that against Iraqi soldiers.