I've just built a data cable to hook up my icom to the sound card, and have been tinkering with FLDIGI to read digital modes. Previously I just set the computer mic next to the radio speaker, and it worked surprisingly well.

Here's a link to a page where you can listen to different examples of digital modes. I found it helpful when I first started.

http://www.kb9ukd.com/digital/

http://www.kb9ukd.com/digital/



DAMNIT!



 

Left hand column second item down.

Thanks guys, those are some great sites. I think it's worth studying for a while to learn the sound of each mode.

Typically you will hear RTTY, PSK31, JT65 and JT9 as the majority of digital signals you will run into on HF.

Digital signals tend to be clustered around various frequecnies based on the modes. For instance on 20 Meters you will find the following:

14.080 USB is typically RTTY

14.070 USB is PSK31

14.076 USB is JT65

14.078 USB is JT9

There a lots of other digital modes like Olivia, Contestia, MFSK, etc. that you can hear on HF, but the four modes I first mentioned by far are the most common.