Propagation News – 15 August 2021
We had another week of minimal sunspot numbers, a low solar flux, but quiet geomagnetic conditions. As a result, DX was a little harder to find. We did have a low-level C-class solar flare on August the 9th that erupted from a plage region on the Sun. Whether this was a precursor to a sunspot appearing we will have to wait and see.
HF conditions have been a little lacklustre with maximum usable frequencies over a 3,000km path struggling to get above 18MHz a lot of the time. Sporadic-E has helped a little, but that is also starting to decline now that the bulk of the season is over.
The best DX may be occurring overnight. Laurie, G3UML reports working Anguilla on 3.799MHz at 0109Z this week – the top 10kHz on 80 metres is often a good DX watering hole. He also reports very good conditions to South America on 20m up to around 2300hrs local and huge signals on 40m from the eastern US. On Thursday morning he also logged K7GI in Arizona on 40m at a genuine S9+. Meanwhile Colin, G3VCQ reports that signals from Japan on 40m in the early evening have been good too. This may be due to the quiet geomagnetic conditions, which allow the ionosphere to settle. The lower SFI means that higher bands may not be open during the day, but the lower bands can come into their own after dark.
As of Thursday, there were no coronal holes on the Sun’s equator so we may expect the good conditions to continue over this weekend. NOAA predicts the solar flux index will start next week in the low 70s. There may be a slight increase to the mid-70s as the week goes on. We may expect slightly unsettled geomagnetic conditions on the 16th with a Kp index of three, but after that, it should settle again to one or two.
VHF and up
The end of last week saw some reasonable Tropo conditions over southern areas extending south into the near continent and down across Biscay to Spain. This area of enhanced lift conditions will be displaced to just affect southwestern parts of the UK and southern Ireland as we move into the new week.
The main change is a return to a more unsettled northwesterly weather type with showers in the first half of next week, so some rain scatter options should be available. By about midweek the next change comes in the form of high pressure returning to northern areas and perhaps more widely later. This is potentially useful for Tropo again, although not as good as that at the end of last week.
Last week’s Perseids meteor shower has probably added some useful new long-lived metallic ionisation into the mix as fuel for Sporadic-E. The coming week shows that jet streams are still present, so maintain your watch list of 10m and 6m beacons to check. The Perseids are a relatively broad-peaked shower, so there will still be some good meteor scatter moments through the coming week as well as the best random meteors around dawn. The Kappa Cygnids shower is active and should peak around the 18th, but with a ZHR of just three it’s a small one.
Moon declination is negative this week so Moon windows will be short. Minimum declination is very close to Tuesday’s perigee where we have lowest path losses.
Category: GB2RS Propagation News
