Propagation News – 23 March 2014

| March 21, 2014

Despite a large number of sunspot groups visible, up to nine on some days, solar activity was only at low levels with numerous C class solar flares taking place every day. On the 20th the only M class solar flare took place; this occurred from a new sunspot group that had just rotated into view. Solar flux levels increased from 136 units to 151 by the 20th. The average was 142. The 90 day solar flux average on the 20th was 157, that’s one unit down on last week. X-ray flux levels declined at first but then increased to end the period at B8.2 units. The average was B6.7 units. Geomagnetic activity was quiet every day. The most disturbed day was the 18th, with an Ap index of only 5 units. The average was Ap 3 units. Solar wind data from the ACE spacecraft saw solar wind speeds decline from 590 kilometres per second on the 14th to 270 by the 19th. Particle densities were low at first but then increased to 50 particles per cubic centimetre on the 20th. Bz showed only modest fluctuations due to a quiet magnetic field and varied no more than minus 8 and plus 6 nanoTeslas.

Finally, the solar forecast for the coming week. The active side of the Sun will be looking our way. Due to two active sunspot regions rotating back into view during the second half of the week, solar activity could increase to moderate levels. Also, solar flux levels should increase and be around the 160s by next weekend. Geomagnetic activity is expected to be at quiet levels every day, provided no Earth-directed coronal mass ejections head our way. Right at the end of the period a small coronal hole disturbance is expected. MUFs during daylight hours at equal latitudes should be well above 30MHz. Darkness hour lows are expected to be around 11MHz. Paths this week to South America should have a maximum usable frequency with a 50 per cent success rate of around 38MHz. The optimum working frequency with a 90 per cent success rate will be about 30MHz. The best time to try this path will be between midday and 1700 hours UTC.

Category: GB2RS Propagation News

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