Came across this video showing a "numbers station." They're thought to be used to send encoded messages via shortwave radio; I've heard a few before when I was a kid, but never knew what they were.
I know virtually nothing about HAM radio, but at one point I was looking into getting a license. There's a lot more to it than just getting onto a cb and talking to random ppl; the reason I was interested was b/c I was heading a space balloon experiment, and in order to communicate with the electronics on it I would have had to have a license. Note that this would have allowed me to control the electronics remotely as well.
Not saying Ohr's wife was using a numbers station or anything else; maybe someone with knowledge can elaborate on what she might have been doing.