Propagation News – 13 July 2014

| July 11, 2014

For three days from the 6th eleven sunspot regions were visible, though most were small there were at least a couple of large and magnetically complex regions. Saying that, solar activity only increased to moderate levels on the 8th, 9th and the 10th when a single M class solar flare took place on each day. The largest solar flare was a M6 on the 8ththat was associated with a non Earth directed coronal mass ejection. Solar flux levels increased from 188 units on the 4th to 201 by the 6th and again on the 8th, levels then declined to 177 units by the 10th. The average was 194 units. The 90 day solar flux average on the 10th was 137, that’s five units up on last week. X-ray flux levels averaged C1 units and varied little day to day. Geomagnetic activity was quiet day and the average was Ap 6 units. Solar wind data from the ACE spacecraft saw solar wind speeds vary between a slow 260 kilometres per second to a normal 420 kilometres per second. Particle densities increased to 24 particles per cubic centimetre on the 9th. Bz never varied between more than minus and plus 8 nanoTeslas throughout the period.

Finally, the solar forecast for the coming week. This week the quiet side of the Sun is expected to rotate into view as the large sunspot groups rotate of the solar disc. Solar activity should only be at low levels and solar flux levels are expected to decline sharply and be around 110 units by next weekend. Geomagnetic activity is expected to be at unsettled levels for the first half of the week due to a recurring coronal hole, activity should then decline to quiet levels for the remainder of the week. MUFs during daylight hours at equal latitudes should be around 21MHz. Darkness hour lows should be about 14MHz. Paths this week to South Africa should have a maximum usable frequency with a 50 percent success rate of around 28MHz. The optimum working frequency with a 90 percent success rate will be about 21MHz. The best time to try this path will be between 1200 and 1500 hours UTC. Sporadic-E is expected to take place most days.

Category: GB2RS Propagation News

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