What is Sporadic E?

It may be that some of our newer members may not be aware of sporadic E and how exciting it can be in the summer months.

At the time of writing, 10m, along with 17m, 15m and 12m and I am told also 6m, has been wide open to Spain (and nowhere else). I am chasing the Spanish IARU 95th anniversary award – see https://iaru95.ure.es/english – and managed a few QSOs towards that.

So what is sporadic E? This is a propagation mode that happens every year during the summer months and sometimes around Christmas. It is totally unrelated to the solar cycle and sunspots, rather it is surmised to be some sort of chemical effect in the E layer of the ionosphere possibly aided by wind sheer patterns and other aspects of the weather. It results in small highly ionised areas in the E layer which reflect radio waves and results in propagation over a few hundred to a thousand miles or so. It happens almost like clockwork, usually starting around the second week of May and continuing to August or so.

Like the name, it is sporadic, it comes and goes. Propagation is very localised depending on where the ionised clouds are located and we tend to have propagation to a fairly small area in Europe or maybe a bit further to Ukraine and the Baltic states. You may hear somebody s9 but someone else 20 mile away hears nothing. What countries you hear changes as the ionised region comes and goes. It may last hours or it may be gone in minutes. But when signals are there they are easy to work, even with 5W and simple antennas.

Diagram showing location of SPoradic-E
Sporadic-E – Image (c)WIkipedia

Sporadic E is largely useful on the higher HF bands, 15m and above, and the lower VHF bands. 6m opens up daily during the summer for sporadic E and there are occasional openings even as high as 2m, but they are
quite rare. The effect can be seen to some extent on the lower bands like 20m but it is harder to differentiate from normal F layer propagation.

Sporadic E cannot be predicted, although some try to forecast it. You have to be tuning the band at the time and never know what will suddenly shoot up out of the noise at s9 – and be ready to work it, it won’t hang around for you. Great fun. And happening much earlier this year (2020) than normal so it may be a good season.


Dave G3YMC