venerdì 10 giugno 2022

Propagation News – 12 June 2022

GB2RS News Team
June 10, 2022

The sunspot number on Wednesday was zero with a solar flux index of 100. Given the high flux numbers we have been seeing this is a little disappointing. The last time the visible disk was officially spotless was December 2021. The upside is that there has been little risk of coronal mass ejections and the Kp index has remained below three for more than a week.

Anecdotal reports showed that the upper HF bands have been quite quiet.

A couple of potential regions are currently behind the Sun’s east limb and will begin to turn into view during the next few days. NOAA predicts that the SFI will increase slightly to perhaps 110 at first and then up to 125 by the 19 June.

While F2-layer openings may be peaking at around 15 metres this month, Sporadic E should bring lots of strong short-skip openings from 14MHz to 28MHz. June is a good month for Es openings. Check out 10 metres at peak Es times of mid-to-late morning and mid-to-late afternoon. Early evening can also bring surprises as well. For novelty’s sake alone, listen out for the HB9HD 10m repeater on 29.650MHz in Switzerland, complete with its musical box ident!

VHF and up:

We start the week with high pressure over mainland Europe. The Hepburn tropo charts predict that we may see lift conditions over southern England this weekend. Paths from locations south of London may be possible into northern France and the low countries, with a slight possibility of extended tropo towards southern France. These opportunities may tend to dissipate as we head into next week.

For stations in the north of England, there may be fewer opportunities for tropo DX as low pressure is predicted to pass to the northwest of the country. Microwave rain scatter opportunities may be available though. From mid-week onwards, the most likely scenario is for low pressure to the north of the UK to clear as high pressure builds from the west, which may bring tropo opportunities to northern areas.

There are always Sporadic-E opportunities available in June, with many good openings reported over the last seven days.

The first half of June is one of the best periods of the year for daylight meteor scatter-DXing but is often masked by Sporadic-E propagation. We have already seen the peak of two daytime meteor showers, namely the Arietids and zeta-Perseids last week, but as they are both characterised by a broad maximum and high ZHR value, they continue to be useful. The best time for them is early morning for North to North-East and South to South-West directions, and early afternoon for North to North-West and South to South-East directions.

With the Moon approaching perigee, its closest point to Earth, on Tuesday, path losses for EME will be at their lowest. This sadly coincides with minimum declination on Wednesday, with short moon visibility windows and low peak moon elevation. 144MHz sky noise will peak on Tuesday and Wednesday at a little over 3100K. (