Here is a pretty neat bit of US Special Forces history. One of my friend’s on FB that is a MACVSOG vet shared this the other day. It is an encryption pad for use over the radio while on missions.
From what I understand, 3 letter combinations were substituted for words or phrases commonly used for daily communication. These changed daily or weekly or some pre determined schedule. I’m sure Hognose could have made better sense out of this for you. Time’s like this I’m sure we all remember how much we miss him.