HF Digital Decoding

From The RadioReference Wiki

Welcome to the HF Digital Decoding article. While tuning around the HF bands, you are very likely to hear a variety of squawks, beeps and other sounds that, at first, defy description. While noise sources are a likely source (typical of HF), at least some will be some sort of digital signal.

Digital signals come in 2 basic flavors - those as used by the amateur radio community, and those used by organizations such as the military, aeronautical, maritime and several other users. While the modes used by amateur radio are, by both law and convention, never encrypted, there are several in the military and others that encrypt their signals so they can't be monitored by the casual listener. The challenge here is to find signals that are readable, or at least, where the user can be identified.

Please see the following articles for more information: