venerdì 23 novembre 2018

Propagation News – 25 November 2018

Last week saw relatively quiet geomagnetic conditions, thanks to a reduction in coronal hole activity. The Kp index never got higher than three, and was usually between zero and two for most of the week. We had a solar flux index high of 72 and a low of 69, which is in keeping with this point in the solar cycle. Speaking of which, a new sunspot with a reversed magnetic signature was spotted on 17 November. As it was at a high solar latitude we can probably associate it with the upcoming Solar Cycle 25. Unfortunately it quickly faded, but the spot marked the second such region in the Sun’s northern hemisphere in as many weeks, suggesting we could be in the early throes of the new solar cycle. Don’t get too excited though, as sunspot minimum is still predicted as being somewhere between September 2019 and early 2020.

Other news was the appearance of sporadic E on 10 metres. This gave many UK amateurs some relatively short skip contacts into southern Europe on November, the 10th. On the 19th we also saw a short-lived F2-layer opening on 10 metres around lunchtime, which just goes to show it pays to watch the bands and, or, the near real-time graphs at

Next week NOAA has the solar flux index around 68 with generally quiet geomagnetic conditions until Saturday, the first, when the K-index is predicted to rise to four or more. Therefore conditions for this weekend’s CQ Worldwide CW contest could be quite reasonable, at least on the bands up to and including 20 metres, with occasional higher band openings.

VHF and up:

It’s looking a bit like a flat week for most VHF propagation modes, with high pressure parked to the north of Shetland. This leaves just a hint of tropo, but confined to the far north across to Scandinavia. The rest of the country is under an easterly flow with a bit too much wind to allow any significant temperature inversions to develop.

The next changes will come as a large area of low pressure moves in from the Atlantic by mid-week, which will bring unsettled weather and remove any chance of tropo, although it may introduce a possibility of some rain scatter on the microwave bands. Other options might include some aurora if we’re lucky and perhaps even some out-of-season sporadic E, like we saw on 10 metres on November, the 10th, with an opening to Corsica and southern France.

There is no meteor shower activity this week, but the December Geminids shower is not too far away!

With maximum declination today, the Moon is up for nearly 12 hours early this week, and with Monday’s perigee, path losses are at their lowest meaning it is a good week for EME.