What use is an F-call? Some days you chew off more than you bargain for. Today I wanted to know a little more about propagation, the radio kind, not the plant variety. Four hours later I'm still reading. Everyone has an opinion, everyone's an expert and some people can even put together a coherent story on their web-site. What did I learn so-far? I didn't know that the Bureau of Meteorology has a Space Weather Branch, it's called IPS or the Ionospheric Prediction Service and their website is full of goodies. Then there's an article by Ian Poole, which appeared in the September 2002 edition of QST magazine, explaining how the Solar Flux, the K index and the A index affect your ability to talk to the other side of the world with your HF set. So, it seems that the numbers are related to things that affect each other. A high Solar Flux is good, but it's adversely affected by a high K index which in turn is represented as an average as an A index. Confused yet? So, the K index, runs between 0 and 9, 9 being a very major storm, 0 being Quiet. Quiet is good, storm is bad. The higher the Solar Flux, the better it is for higher HF frequencies. The Solar Flux needs to build up, takes a few days, so, you need Quiet and high Solar Flux for a few days and magic happens. I'm not confident enough with all this to tell you what to look for, but it seems that a Solar Flux of 150 or more for a few days with a K index below 2 will give you a good chance of getting some DX contact. Now I realise that this might just be gobbledygook for you, in fact, four hours ago, it was for me too, but now when someone talks about the Solar Flux being high, at least I have an idea of what on earth they're talking about. Next stop, figuring out how to read propagation maps. I'm Onno, VK6FLAB