Propagation News – 12 August 2018

| August 10, 2018

The Sun remained spotless this week as the solar flux index stuck resolutely around the 70 mark. The tiny sunspot that made an appearance on the first of August didn’t come to much and had vanished by the third.

This underlines that we must be getting closer to sunspot minimum, although don’t expect to see any massive upturn until 2019.

Geomagnetic conditions were mostly settled last week, although the effects of a coronal hole did send the K-index to three on Tuesday, the 7th.

Another equatorial-located coronal hole was rotating into position as this report was being written, so prepare for potentially unsettled conditions this weekend, the 11th and 12th.

Looking further ahead NOAA predicts unsettled geomagnetic conditions around the 17th and again on the 20th and 21st due to coronal hole activity. The solar flux will remain around the 70 mark.

HF wise, conditions have been a little lacklustre with large parts of the bands devoid of signals, apart from the FT8 watering holes.

The 40, 30 and 20m bands still provide the most activity during daylight hours, with occasional openings on 17m metres. 80m and 40m are the “go to” bands after sunset, which of course is now getting earlier each day.

However, the ionosonde data at show there have been some consistent post-sunset HF openings up to 18MHz occurring around 2100UTC, so don’t write-off HF after dark.

And finally, don’t forget it is International Lighthouse and Lightship Weekend on 18 and 19 August.

VHF and up

Last Sunday EI3KD worked D4Z on the Cape Verde Islands off the coast of Africa on 144 MHz, at 4163km. This CW contact sets a new Region One tropo record.

After all the tropo excitement, meteor scatter gets only secondary billing in the VHF news this week. The Perseids meteor shower’s broad peak hits maximum this Sunday so the VHF meteor scatter frequencies should be buzzing with meteor pings. Check out the 50/70 and 144 MHz chats to see where the activity is and look upwards for shooting stars if you have dark skies.

The next week looks likely to change our world of constant tropo into a more unsettled weather type with low pressure systems and fronts moving towards the country. This will mean that rain scatter will come to the fore on the GHz bands. There could still be a little tropo around, especially over sea paths in the south, but not very reliable ones.

Looking at sporadic E propagation, last week we continued to get evening digimode openings to the US. We will have a return to the unsettled weather, which implies the return of a jet stream pattern, mainly across northern Europe.

This will favour paths across to Scandinavia, whereas to the south we may have to rely upon either weaker jet streams or upper ridge patterns to come to our rescue.

August is still part of the sporadic E season, but it is not as widespread as earlier and perhaps harder to work.

Moon declination is high but goes negative on Wednesday so there are still plenty of EME opportunities available, with increasing losses.

Category: GB2RS Propagation News