These call signs all contain one or more slashes, are less predictable, and not as common. This is what makes them difficult.

For each difficult call sign, keyboard-copy or pencil-copy it. First, the call sign is sent in Morse code. Then it is spoken. And finally, it is sent again in More code. If you missed it the first time it was sent, the second time allows you an opportunity to learn it.

73 de AD0WE!