Propagation News 29 September 2013

| September 27, 2013

Yet another week where solar activity looks like solar minimum rather than solar maximum, as where we are now. Despite up to 7 sunspot groups visible solar activity was at very low levels except for 8 small C class solar flares that took place, 4 on the 20th, 3 the following day and one on the 24th. Solar flux varied little day to day and the average was 110 units. The 90 day solar flux level on the 26th was the same level as last week at 111 units. X-ray flux units declined slightly from B2.8 units on the 20th to B1.9 by the 23rd and the 24th. The average was B2.3 units. Geomagnetic activity was quiet everyday, however, activity did increase slightly on the 24th but the Ap index only reached 10 units that day. The average was 6 units. Solar wind data from the ACE spacecraft saw solar wind speeds increase from 340 kilometres per second to 460 by the 24th. Particle densities were low except for a brief increase to 60 particles per cubic centimetre around midday on the 24th. Bz varied between minus 3 and plus 4 nanoTeslas on the quiet days and between minus 10 and plus 11 nanoTeslas during the 24th.

And finally the solar forecast for the coming week. With the quiet side of the Sun expected to be looking our way solar activity is expected to be at very low levels. There is a chance though that activity could increase to low levels on some days. Solar flux levels are expected to be around the 100 mark for most of the week. Geomagnetic activity could be slightly unsettled today and tomorrow due to a small recurring coronal hole but then decline to quiet levels for the remainder of the week. MUFs during daylight hours at equal latitudes 22MHz for the south and 19MHz for the north. Darkness hour lows should be about 11MHz. Paths this week to Australia should have a maximum usable frequency with a 50 per cent success rate of around 25MHz. The optimum working frequency with a 90 per cent success rate will be around 20MHz. The best time to try this path will be between 0800 and midday UTC.

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

Category: GB2RS Propagation News

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