Ahhh, good ol' "HMO1". Previously V01 and V02 w/o the digital.
Great resource to listen to the various stations if you haven't already, lots of history and newsletters too.
http://www.numbersoddities.nl/Also Priyom, excellent site. The "Enigma 2000" names for the stations (like "HM01" are useful shorthand for talking about the subject, they're nothing official, just useful names. The Enigma newsletter is from a UK point of view, lots of good history and loggings there, interesting cast of characters.
These kind of stations, very roughly speaking, really hit their heyday during the Cold War, but morse versions go back to pre-WW2, at least! Actually, Amundsen used a cypher to telegraph his announcement after he made it to the South Pole in 1911, and the idea of one-time pads is (AFAIK) way older than that.
Cheers!