Propagation – 14 April 2013

| April 14, 2013

And now the solar factual data for the period from Friday the 5th to Thursday the 11th of April compiled by Neil Clarke, G0CAS on Friday the 12th of April.

During the period many sunspot groups were visible with up to ten groups on the 5th, some of these groups were large and looked rather threatening. Right at the start of the period, an impulsive M2 solar flare took place and then, at the end of the period, a much larger M6 solar flare occurred. An Earth directed coronal mass ejection was associated with this flare. Solar flux levels increased from 134 units on the 5th to 148 by the 10th. The average was 140 units. The 90 day solar flux average on the 11th was 113 units, that’s one unit down on last week. X-ray flux levels increased from B3.6 units on the 5th to B7 by the 10th. The average was B5.1 units. Geomagnetic activity was quiet everyday with an average of Ap 4 units. Solar wind data from the ACE spacecraft saw solar wind speeds increase erratically from a slow 250 kilometres per second on the 5th to 500 by the 11th. Particle densities were low everyday except for the 10th, which increased to 20 particles per cubic centimetre. Bz never varied more than minus 7 and plus 8 nanoTeslas for the entire period.

And finally the solar forecast for the coming week. Later this week the quiet side of the Sun is expected to be rotating into view. Solar activity is expected to be low but activity could increase to moderate levels with the occasional M class solar flare taking place. Solar flux levels should decline and be around the 100 mark later in the week. Geomagnetic activity could be at ‘storm levels’ due to the coronal mass ejection that departed the Sun on the 11th. Activity should then decline for the rest of the period to quiet levels. MUFs during daylight hours at equal latitudes should be around 23MHz for the south and 20MHz for the north. Darkness hour lows are expected to be about 11MHz. 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 22MHz. The optimum working frequency with a 90 per cent success rate will be about 17MHz. The best time to try this path will be between 1600 and 2100 hours UTC.

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

Category: GB2RS Propagation News

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