Propquest – near real-time propagation tool


This near real-time propagation tool was developed by Jim Bacon G3YLA.

It takes data from digisondes, notably Fairford in Gloucestershire in the Cotswolds (which is part of the USAF Nexion network of monitoring stations) and Chilton in Oxfordshire, managed by the Rutherford Appleton Laboratory.

From these it determines the critical frequency (FoF2), which is the frequency at which signals launched vertically into the ionosphere are just returned back to Earth.

From the critical frequency we can extrapolate the maximum usable frequency available for different path lengths – 100, 500, 100 and 3000km.

Of course, for a local net you will be using a near vertical incidence skywave (NVIS) refraction from the F2 layer, so the foF2 is a good guide for conditions.

If you are just interested in the close-in UK conditions for your local nets, then switch off the 3000km F2 MUF (just click on the legend at the bottom of the screen) to see the foF2 or short skip 100km detail more clearly.

Alternatively, the 3000km MUF is a good guide to HF conditions for DX.

There is also a section on Sporadic E, which is a phenomenon that usually shows itself in the UK from late April to the end of August. A daily Es blog is written by Jim G3YLA during the summer season and there are also high-level wind charts as wind shear is thought to be a major contributor to Es.