Propagation News

| November 18, 2012

And now the solar factual data for the period from Friday the 9th to the 15th of November compiled by Neil Clarke, G0CAS on Friday the 16th of November.

Several large and complex sunspot groups were visible during the period but only one produced any sizable solar flares. Solar activity was low on the 9th and the 10th and again on the 15th. On the remaining days activity increased to moderate levels and high on the 13th. The largest solar flare was a M6 that took place early on the 13th. Several coronal mass ejections took place but none were directed towards Earth. Solar flux levels increased from 115 units on the 9th to 146 by the 13th, levels then declined slightly to 141 by the 15th. The average was 135 units. The 90 day solar flux average on the 15th was 119 units, that’s two units up on last week. X-ray flux levels increased from B3.1 units on the 9th to B5.9 on the 12th. The average was B4.6 units. Geomagnetic activity was very quiet until the 13th when an anticipated coronal hole disturbance arrived. The most disturbed day was the 14th, with an Ap index of 31 units. The average was Ap 9 units. Solar wind data from the ACE spacecraft saw solar wind speeds increase from a slow 270 kilometres per second to 470 by the 14th. Particle densities were low but increased to 77 particles per cubic centimetre during the 12th. Bz varied between minus 1 and plus 5 nanoTeslas on the quietest day and between minus 19 and plus 20 nanoTeslas during the disturbance. Auroral contacts were made on 50MHz but were confined to high latitudes late on the 13th and again during the 14th. Daytime highs decreased by several MHz during the disturbance.

And finally the solar forecast for the coming week. At first the active side of the Sun will be looking our way but as the week progresses it will rotate out of view. Solar activity is expected to be low but there is a chance that activity could increase to moderate levels, especially during the first half of the week. Solar flux levels are expected to decline and be around the 120 mark by next weekend. Geomagnetic activity is expected to be quiet every day, however, there is a slight chance that a solar flare related coronal mass ejection could head our way; if one does than activity would increase. MUFs during daylight hours at equal latitudes should be around or slightly exceed 30MHz during most days. Darkness hour lows should be around 9MHz. Paths this week to the east coast of North America should have a maximum usable frequency with a 50 per cent success rate of around 29MHz. The optimum working frequency with a 90 per cent success rate should be about 24MHz. The best time to try this path will be between 1400 and 1700 hours UTC.

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

Category: GB2RS Propagation News

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