He may have been testing. I picked up very nice mid-70's Sony portable cassette player/recorder at a yard sale. I used in the field for years as it had a line output. It had a Jimmy Swaggart tape in it when I bought it. I used Jimmy's rants for tuning up and testing for years.
My guess is a lot of weird little snippets of music and programming you hear from time to time is the same thing, checking the audio chain before a tx or comparing antenna set-ups.