GB2RS News

And now the solar factual data for the period from the 6th to the 22nd of August, compiled by Neil Clarke, G0CAS on the 23rd of August.

Solar activity for the first three days started at low levels with C class solar flares taking place on those days. The largest flare was a C4 which occurred on the 18th, when the spot group had rotated out of sight a day earlier. The remaining days activity declined to very low levels. The solar disc became spotless on the 21st and the 22nd. Solar flux levels declined from 85 units on the 16th to 75 by the 22nd. The average was 79 units. The 90 day solar flux average on the 22nd was the same level as last week at 77 units. X-ray flux levels declined from B1.4 units on the 16th and the 17th to A4.9 by the 22nd. The average was A8.2 units. Despite several coronal mass ejections caught on camera by the SOHO spacecraft none headed our way and geomagnetic activity remained at quiet levels everyday with the average was Ap 5 units. Solar wind data from the ACE spacecraft saw solar wind speeds declined gradually from 410 kilometres per second on the 16th to a slow 260 by the 22nd. Particle densities were low throughout. Bz with a quiet magnetic showed variations no more than minus 6 and plus 5 nanoTeslas for the period.
And now the solar forecast. This week the slightly more active side of the Sun is expected to be looking our way. Solar activity on occasions could increase to low, but most days should remain at very low levels. Solar flux levels are expected to be into the 80’s for most of the week or the 90’s if any substantial groups unexpectedly appear. Geomagnetic activity is expected to be at quiet levels everyday. MUFs during daylight hours at equal latitudes should be around 21MHz for the south and 18MHz for the north. Darkness hour lows should be about 10MHz. Paths this week to Japan should have a maximum usable frequency with a 50 per cent success rate of around 19MHz. The optimum working frequency with a 90 per cent success rate will be about 15MHz. The best time to try this path will be between 1000 and 1300 hours. Just a remainder that the summer sporadic-E season is just about over but for the coming few weeks, short localised openings can still take place on some days. Also, the winter season will take place from the middle of December to the middle of January. GB2RS will remind you nearer the time.

And that’s all for this week from the propagation team.

The RSGB propagation news is also available in a Saturday update, posted every Saturday evening and for more on propagation generally, see http://www.rsgb.org/committees/psc.php

Also see the UK HF Propagation Prediction pages by Gwyn Williams, G4FKH