I recently received my amateur radio general license and setup my station. One of the first formats I was interested in was JT65, as it provides good reception, even with poor signals, and it has a fairly structured format which makes it a bit easier to start with. So, what is JT65? From Wikipedia:
JT65, developed and released in late 2003,[3] is intended for extremely weak but slowly varying signals, such as those found on troposcatter or Earth-Moon-Earth (EME, or “moonbounce”) paths.