Propagation News – 4 August 2013

Up to seven sunspot regions were visible on some days but none were very active. Once again this week solar activity was at low levels with only small strength C class solar flares taking place except for the 1st when activity declined to very low and no C class solar flares occurred. Only one M class solar flare took place during July and that was right at the start of the month, not really what is expected at solar maximum. Solar flux levels showed little daily variation and averaged 110 units. The 90 day solar flux average on the 1st was 118 units, that’s three units down on last week. X-ray flux levels increased from B3.3 units on the 26th to B4.7 before declining to B3 by the end of the period. The average was B3.7 units. Geomagnetic activity started at unsettled levels with an Ap index of 14 units on the 26th; this was due to a small coronal hole. Activity was quiet on the remaining days. The average was Ap 8 units. Solar wind data from the ACE spacecraft saw solar wind speeds decrease from 620 kilometres per second on the 26th to 320 by the 1st. Particle densities were slightly elevated at first with 14 particles per cubic centimetre recorded on the 26th but then declined to single figures for the rest of the period. Bz varied between minus 8 and plus 5 nanoTeslas on the 26th and as low as minus and plus 4 nanoTeslas on the quieter days.

And finally the solar forecast for the coming week. This week solar activity is expected to be at low levels. All the visible sunspot groups should be small and not have the capability to produce any large solar flares. Solar flux levels are expected to be around the 110 mark. Geomagnetic activity is expected to be mostly quiet everyday. MUFs during daylight hours at equal latitudes should be around 22MHz for the south and 19MHz for the north. Darkness hour lows are expected to be about 12MHz. Paths this week to Australia should have a maximum usable frequency with a 50 per cent success rate of around 21MHz. 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 077 and 1100 hours UTC. Sporadic-E is expected to take place some days.

Category: GB2RS Propagation News