Jim Bacon G3YLA has developed an online tool to show near real-time critical frequency over the UK and the predicted maximum usable frequency over different paths

The plots are designed to show the near real-time evolution of the critical frequency ( foF2 ) of the F2 layer as measured by the international network of ionosondes. The display system is setup to process data from the USAF ionosonde at RAF Fairford in Gloucestershire on the Cotswolds.

These data are automatically decoded from ionograms and where conditions do not allow a value to be determined automatically, a gap appears in the graph. The displays depend upon the data being uploaded from the measurement station and therefore depends upon many operational factors outside our control. Outages are usually of short duration, so keep checking periodically if data is missing.

The purpose of these graphs is to allow radio amateurs to use this professional ionosonde data to improve their understanding of radio propagation conditions heard on the air in relation to actual measured conditions on the ionosphere, as they happen.

Propagation tool - http://www.convectiveweather.co.uk/ionosphere/