Propagation News – 24 August 2014

Several small sunspot regions were visible every day, however, on the 21st a new active sunspot region rotated into view. Until then solar activity was low with only a small number of C class solar flares taking place each day, but on the 21st an impulsive M3 solar flare took place increasing activity to moderate levels. Solar flux levels took a small dip to 111 units on the 18th and the 19th but started to increase with the approaching new sunspot region and ended the period at 128 units. The average was 115 units. The 90 day solar flux average on the 21st was 126 units, that’s one unit down on last week. X-ray flux levels increased from B2.6 units to B5.8 by the 21st and the average was B3.6 units. Geomagnetic activity was at quiet levels except for the 19th which increased to Ap 15 units and 12 on the 21st. The average was Ap 7 units. Solar wind data from the ACE spacecraft saw solar wind speeds decline from 380 to 260 kilometres per second by the 16th but then increased to 450 kilometres per second on the 19th. Particle densities were low but increased to 30 particles per cubic centimetre on the 19th. Bz varied between minus 5 and plus 2 nanoTeslas on the quietest day and between minus 18 and plus 12 on the 19th that was the most disturbed day.

Now the solar forecast for the coming week. This week the more active side of the Sun will rotate into view, solar flare activity is expected to increase to moderate levels, on some days. There will be a slight chance of a major solar flare taking place. Solar flux levels should increase and be around the 150s later in the week. Geomagnetic activity should be quiet at first but around midweek a small recurring disturbance is expected. Activity should then decline but increase again later at the weekend. MUFs during daylight hours at equal latitudes should be around 23MHz. Darkness hour lows should be about 13MHz. Paths this week to South America should have a maximum usable frequency with a 50 percent success rate of around 30MHz. The optimum working frequency with a 90 percent success rate will be about 23MHz. The best time to try this path will be between 1400 and 1800 hours UTC.

Category: GB2RS Propagation News