Past Talk – About Sporadic E – see below for video

23rd September 2022 MSARS and Online

In strawberry season, not all fruits in the garden are strawberries. This analogy illustrates the assumption that many radio hams make about Sporadic E propagation. Because it’s June, they assume that all VHF contacts are made via Sporadic E. This presentation strives to explain Sporadic E (Es) propagation and debunk such assumption.

Sporadic E has many variables – the Sun’s radiation, wind shear, winds and tides, the geomagnetic field, disturbance of the geomagnetic field, meteor characteristics, time, latitude, and tropospheric effects (like mountain turbulence, jet streams and thunderstorms) creating atmospheric gravity waves that propagate upwards. As a result of the many variables, it’s impossible to predict when an Es opening will occur. Es is most prevalent over the summer months and less frequent in winter.

See for the presentation. Or see on this site.

Past Talk – Communication via the aurora – see below for video

12th November 2021 MSARS and Online

Communication by radio amateurs via the aurora borealis (and indeed via the aurora australis in the southern hemisphere) can only be described as occasional. Like Sporadic E, it’s a mechanism supported when several atmospheric and geomagnetic effects align. And it occurs in the thermosphere, around 110km up, and about 50˚ to 60˚ North. But just because there’s a visible light show does not mean radio propagation will be supported. So why, and how often, do radio auroras occur? Can I participate south of the Scotland/England border? What do I have to do to exploit an aurora? How will I know if there’s an aurora in progress? How can I design my station to maximise both chances and DX outcome? And how can I predict when a radio aurora is going to happen? John answered these questions while covering the full science and practice of communications via radio auroras.

See for the presentation. Or see on this site.