Since the Roger Tory Peterson Guide Institute is in my local county, I guess I should adapt his famous birding field guide concept, and apply it to the often asked question about recognizing digital modes.
Roger Tory Peterson laid out his guide in a logical manner , clustering similar specifies, and "types" of birds close together in his book. His illustrations emphasized obviously distinctive features that could be quickly used to "I.D." the bird and then some of the less obvious features (like tail feathers). He also gave close up views , and "in flight" views. The same concepts could easily be employed for a digital mode guide, easier for hams versus SWL because hams do not use as many digital modes. Roger Tory Peterson also emphasized the "song" of the bird , the motion, and the habitat. Stealing all the ideas for digital mode recognition , the key facts would be Habitat ------ where on the band is it ? Size? How wide on a waterfall is it ? 31 Hz? 500 Hz ? 2.7 Khz ? Song- Single or multi-tones ? High pitched, low pitched ? A constant tone or rhythmic pauses in tones? Markings: Two vertical lines spaced 170Hz apart? multi-layered markings in a complex 1000 Hz area ? Using the above principles, The Crows , Sparrows, and Robins of the digital modes (PSK31, RTTY, and JT65A) should be so "common" that you can generally recognize them at a quick glance or simply by hearing their "song". Being able to do this, would take care of about 80% of the signals you are likely to hear. Becoming more of a "habitat" expert would easily add another 10% of the possible signals that you could recognize quickly. The remaining 10% will take some work , varying combinations of song and size, within the Thor, Olivia, Domino, families. I will put some illustrations together in RTP fashion in the near future. Andy K3Uk
