Propagation News – 3 May 2020

| May 1, 2020

Sunspots are like buses—you wait all month and two turn up at once! Even more interesting is that the sunspot groups are from two different cycles. The first group, AR2760, was from the outgoing Solar Cycle 24 and the second sunspot, AR2762, is from the new Solar Cycle 25. We know this due to their magnetic signatures and the relative location of the spots on the Sun’s surface. AR2762 was a high-latitude spot, while AR2760 was almost on the solar equator. In any event, both spots were very minor and had little or no effect on the solar flux index, which hovered around 69-71. Geomagnetic conditions were more settled, with the Kp index remaining at zero or one towards the end of the week.

The highlight for the week was the 2020 summer sporadic E season on 10m, which is growing in strength. Stations in Gibraltar, Spain, Romania, Finland, Norway and others were all workable on 10m FT8 on Thursday morning, although it would have been nice to see a little more activity on CW and SSB, but more on that later.

We expect solar activity to remain at very low levels in the short term, with the solar flux index remaining at around 68-70. Geomagnetic conditions are likely to remain settled, other than this weekend when SWPC predicts the impact of particles from a solar coronal hole. NOAA disagrees and predicts that geomagnetic field activity is expected to reach active levels on Tuesday, 5 May in response to a high-speed solar wind stream. It will be interesting to see who is correct.

VHF and up

A small high crosses the country this Sunday and pauses over the North Sea on Monday, giving a tropo option for most areas. This is soon followed by a further spell of unsettled weather with a good potential for rain scatter in the south over the middle of the week. Other weather models retain the high pressure, and even the unsettled model relents and brings another high to the north-west of Scotland, which will start to build across the country from the west to bring a fine, tropo end to the week.

As for sporadic E prospects, the next week does have some useful jet streams in good positions for paths from the UK. Early in the season paths can be fleeting, but keep a watch on 10m activity and then follow the opening higher in frequency as it develops on 6m, 4m and eventually 2m if we are very lucky.

There is a big difference between FT8 and CW/SSB performance, but follow the many wonderful clusters and logging sites to see where the openings are. Try the daily sporadic E blog on to get an idea of the significant jet streams. It will have changes to the charts and a trial of the sporadic E probability index (EPI). There is plenty to investigate in the 2020 sporadic E season.

There are two meteor showers upcoming this week. The larger eta-Aquarids is on Tuesday and the eta-Lyrids occur on Thursday.

Moon declination goes negative on Tuesday followed by perigee on Wednesday with lowest EME path losses. 144 MHz sky noise will be very high this Sunday and for the early part of next week.

Category: GB2RS Propagation News