If you have visited my site home page today you may have noticed the black "Propadex" button in the left hand sidebar just below my WebProp box. I first saw this in the sidebar on W9OY's blog. Since it bears the legend "QSONET.COM" I thought it must show activity levels on the QSONET fake ham radio system. But in fact, it looks as if it might be a very useful propagation indicator for those of us who like to use real radio.
There doesn't seem to be much information about Propadex other than what you can glean from clicking on the image itself, but apparently it is a propagation index derived from real-time ionospheric F0F2 measurements made by the US Air Force Solar Telescope Network in San Vito, Italy.
The index is relative to conditions averaged over a 60-day period for the same time of day. It shows how much better or worse than average the F0F2 (or Maximum Usable Frequency, MUF) is, in units of 10Hz. So if the index is +100 it means that the MUF is 1MHz higher than the average for this time of day. If it is negative, it shows that conditions are worse than average. It doesn't tell you what the MUF actually is, so you still need to know what average conditions are for it to be useful.
The graph to the left of the number shows the previous eight hours of data. So this could give you an idea of how conditions are changing.
It will be interesting to see how well this indicator correlates with perceived band conditions. It would also be interesting to find out where the data comes from, with a view to adding this indicator to WebProp if it proves to be useful. Another project to add to my ham radio To-Do list!