Don’s first talk about Utility Listening was back in 1990 when he described the Hoka Code 3 Data Mode Decoder. At that time there were many different modes which are, for the most part, no longer used.
Since that time, many of those who made the transmissions have changed to satellite communications. However, now it is realized that satellites can be vulnerable as well as costly. Some Civil Authorities and the Military have  been migrating back to HF communications. The use of complicated software negates some of the shortcomings of HF drop-outs and the overall result is still reliable and much cheaper. While still using satellites, the HF communications provide an effective back up.
Don demonstrated the latest decoding software and played several recordings of transmissions using modern modes of modulation. Although much is known about the parameters of the transmissions, most of the results are encrypted. There are, however,
some transmissions which are not. They are mostly weather related and some news services.