HFDL - What does it mean?

[W1HD]

I'm successfully decoding HFDL but (maybe because I'm not a pilot) I don't understand much of the content.

Is there a web site out there that explains what those texts mean?

 

[a417]

I'm successfully decoding HFDL but (maybe because I'm not a pilot) I don't understand much of the content.

Is there a web site out there that explains what those texts mean?

Beyond google and wikipedia entries for HFDL and things like approved abbreviation lists?