I remember (badly) a discussion some 35 years ago with an aged “G”  who remembered a system of codification of transmission style in punched cards at Bletchley during the war.   He said that they codified “fists” with certain criteria on punched cards and the you could see if a “newly” identified station was an old operator by inserting rods matching the fist.   So you could see if Joe Blogs who used to be a radio op on ship X has moved to ship Y or an operator at Moscow airport was now somewhere else…..

I could not find much on the punched card/rods however similar information on an approach “TINA” is covered in some places on the web.  An article on this subject can be found here:  Allied Analysis of Electronic Transmissions in WWII by Jerry Proc VE3FAB

Try doing that with a modern TCO stabilised transceiver keyed with an auto-keyer!

Simon G0FOZ