For fun, I downloaded cocoaModem: a program that decodes many modes, including RTTY, PSK31, and SITOR-B. SITOR-B is similar to RTTY, but is used by the USCG to send out weather alerts to ships at sea. It took me a few tries, but I finally got the hang of it (it’s a little odd compared to fldigi, which seemed straightforward, but which sadly just runs on Linux, not my macbook), and here’s a screendump of it decoding: