GB2RS News

Now the solar factual data for the period from the 1st to the 8th of March, compiled by Neil Clarke, G0CAS on the 8th of March.

The latest smoothed monthly sunspot numbers are available for June, July and August 2009 and are 2.7, 3.6 and 4.8 respectively.
Sunspots were visible every day except for the 6th and the 7th. These are the first spotless days since the 19th of January and only the fourth day so far this year. Only one C class solar flare occurred, this was on the 4th. The remaining day’s solar activity was very low. Solar flux levels varied little and averaged 79 units. The 90 day solar flux average on the 7th was 81 units, that’s the same level as last week. X-ray flux levels increased slightly from A2.2 units on the 1st and the 2nd to A6.6 by the 4th. The average was A3.7 units. Geomagnetic activity was quiet with the Ap index in single figures everyday. The average was Ap 4 units. Solar wind data from the ACE spacecraft saw solar wind speeds vary between 320 and 470 kilometres per second. Particle densities were low throughout and were never more than 10 particles per cubic centimetre. Bz never varied more than minus 9 and plus 10 nanoTeslas during the period.
All this added up to stable radio weather, in which the HF bands were in good shape. North-south paths to Africa and South America were improved as their seasonal peak approached, while there were also openings on 24MHz to Hawaii and the US West Coast in the early evening. Incidentally, even during this geomagnetically quiet period, both visual and radio aurora were reported on several days – but apparently much too far north to be accessible to UK operators.
And finally the solar forecast. This week the quiet side of the Sun is expected to be looking our way. Saying that, while the Sun is in its present state sunspot groups can appear at any time. Solar activity is expected to be very low to low. Solar flux levels should be in the 80’s for most of the week but could decline into the 70’s towards next weekend. Geomagnetic activity could be unsettled today and tomorrow due to a recurring coronal hole after which activity should be quiet for the rest of the period. MUFs during daylight hours at equal latitudes should be about 23MHz for the south and 20MHz for the north. Darkness hour lows should be around 8MHz. Paths this week to India should have a maximum usable frequency with a 50 per cent success rate of around 24MHz. The optimum working frequency with a 90 per cent success rate will be about 19MHz. The best time to try this path will be between 1000 and 1400 UTC.
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