The confusing use of 4 different methods of calling out channel frequency for RTTY and FSK, is not a problem unique to ham radio.
The entire communication industry, regulatory entities, and standard organisations of the world, have all been using a variety of methods to describe channel frequency for various types of signals, for various reasons. In some situations for commercial or governmental communications, the confusion between the different channel frequency methods has led to significant problems. The seriousness of this problem may not really be quite so intense in ham radio for HF digital, and sometimes it can be humorous. I had to laugh at the irony of the complaint from one operator who was very angry, because a "DX spot" he had obtained from the cluster for a RTTY DX station wasn't exactly on the frequency when he tuned it! On the other hand, digital HF networks used by hams for data communications rely upon vary accurate frequency netting. It is advantageous for the members of those nets to understand the standard method for describing channel frequency used by that net. Bonnie KQ6XA
