The solar factual data for the period from 28 April to 4 May , compiled by Neil Clarke, G0CAS and Martin Harrison, G3USF

The solar disc was spotless but on the 4th a small sunspot group emerged. Its location and magnetic footprint confirms that this group belongs to the new cycle and is the first group of the new cycle to be located in the Sun’s southern hemisphere. Solar flux levels averaged 68 units and only varied by a one unit day to day. The 90 day solar flux average on the 4th was 71 units, that’s one down on last week. X-ray flux levels remained below the minimum reporting level throughout. Geomagnetic activity started at unsettled levels in response to the coronal mass ejection on the 26th. No sooner had that arrived then the effects from a coronal hole also arrived. Activity was unsettled everyday and the average was Ap 10 units. The ACE spacecraft saw solar wind speeds increase from 370 kilometres per second to 630 by the 4th. Particle densities increased to 43 particles per cubic centimetre on the 30th. The remaining days levels were around 10 particles per cubic centimetre. Bz varied between minus 8 and plus 9 nanoTeslas throughout.

HF propagation deteriorated with the arrival of coronal hole disturbances and F2 daytime critical frequencies fell from 5.3MHz to only 4.1Mhz on the 24th. VHF auroral propagation briefly reached as far south as southern Britain on the 23rd but was mostly confined to high latitudes. The good news has been the first big sporadic-E opening of the season on the afternoon of the 22nd and 70MHz contacts with Italy - though these were mainly by meteor scatter.

And now the solar forecast. This week solar activity is expected to be very low. The solar disc could be spotless on some days. Solar flux levels should be around the 70 mark for most of the week. Geomagnetic activity is expected to be mostly quiet all week. MUFs during daylight hours at equal latitudes should be about 18MHz for the south and 15MHz for the north. The darkness hour lows are expected to be around 9MHz. Paths this week to South Africa 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 should be about 19MHz. The best time to try this path will be between 0800 and 1600 hours UTC. Sporadic-E is expected to take place on some days.

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