It's news to me that sonograms use radio waves.
The problem was the hardware. Individuals couldn't afford a PDP 1. My first personal computer was an Apple II in 1981 and it cost $6,000, real money then. Universities had computers and the ones in science labs got used for all sorts of cool things.
The cards I remember were 80 columns. Generally you got one character per column. (6-bit characters to begin with and EBCDIC later on.) You could use them in a variety of 'binary' modes, which gives you a theoretical maximum of 80 x 12 = 960 bifs or 120 bytes. That was generally only used for run-time decks, not for programs or raw information.
"Can you program?" "Well, I'm literate, if that's what you mean!"