Propagation News – 7 September 2014

| September 5, 2014

Solar activity was low with numerous C class solar flares taking place everyday, these got stronger as a couple of sunspot regions rotated into view. Solar activity increased to moderate levels on the 3rd and the 4th once these regions rotated fully into view. The largest solar flare was a M2 class which occurred on the 3rd. Solar flux levels increased from 120 units on the 29th to 138 by the 3rd. The average was 129 units. The 90 day solar flux average on the 4th was 130, that’s one unit up on last week. X-ray flux levels increased from B3.5 units on the 29th to C1.2 by the 2nd. The average was B7.2 units. Geomagnetic activity was unsettled everyday, except for the 4th, which was quiet, the most disturbed day was the 29th with an Ap index of 20 units. The cause of this prolonged disturbance was a very slow moving coronal mass ejection and in the latter days of the period possibly a weak coronal hole disturbance. The average was Ap 13 units. Solar wind data from the ACE spacecraft saw solar wind speeds vary between 350 and 490 kilometres per second. Particle densities were low everyday. Bz varied between minus 9 and plus 8 nanoTeslas on the most disturbed day and between minus 5 and plus 4 nanoTeslas on the quietest day.

Now the solar forecast for the coming week. This week at least two active sunspot regions will have already rotated into view. Solar activity is expected to be moderate on some days. Solar flux levels are expected to increase and be in the 140’s for most of the week. Geomagnetic activity is expected to be quiet most days, there is a slight chance though that an Earth directed coronal mass ejection could head our way. MUFs during daylight hours at equal latitudes are expected to be around 23MHz. Darkness hour lows should be about 10MHz. Paths this week to South Africa should have a maximum usable frequency with a 50 percent success rate of around 31MHz. The optimum working frequency with a 90 percent success rate will be about 24MHz. The best time to try this path will be between 1000 and 1600 hours UTC.

Category: GB2RS Propagation News