Propagation News

| December 2, 2012

And now the solar factual data for the period from Friday the 23rd to the 29th of November compiled by Neil Clarke, G0CAS on Friday the 30th of November

Several large and magnetically complex sunspot regions appeared during the period and most produced a number of C class solar flares every day. However, solar activity increased to moderate levels on the 27th and the 28th when two M class solar flares took place on the 27th and one on the next day. Solar flux levels declined from 126 units on the 23rd to 113 by the 29th. The average was 119 units. The 90 day solar flux average on the 29th was 123 units, that’s one unit up on last week. X-ray flux levels increased to peak at B5.8 units on the 26th but then declined to B3.9 by the end of the period. The average was B3.9 units. Geomagnetic activity was quiet every day except for the 24th, when a coronal mass ejection arrived and a weak geomagnetic disturbance took place during the first half of the day. The Ap index for the day was 15 units The average was Ap 5 units. Solar wind data from the ACE spacecraft saw solar wind speeds increase from 300 kilometres per second on the 23rd to 550 by the 26th. Speeds then gradually declined to 330 kilometres per second by the end of the period. Particle densities increased to 22 particles per cubic centimetre on the 23rd and then increased further the next day to 44 particles per cubic centimetre. Densities then returned to low levels for the remainder of the period. Bz varied between minus 11 and plus 13 nanoTeslas during the disturbance and between minus and plus 3 nanoTeslas on the quiet days.

And finally the solar forecast for the coming week. This week the quiet side of the Sun is expected to be looking our way. There are though a couple of regions that will remain visible. Solar activity should be at low levels on most days but could increase to moderate levels on some days. Solar flux levels should be around 110 units but could start to increase after midweek. Geomagnetic activity should be at active levels at first due to a recurring coronal hole. However, from midweek activity should have returned to quiet levels. MUFs during daylight hours should be around 26MHz for the south and 23MHz for the north. Darkness hour lows should be about 8MHz. Paths this week to Australia should have a maximum usable frequency with a 50 per cent success rate of around 27MHz. The optimum working frequency with a 90 per cent success rate will be about 22MHz. The best time to try this path will be between 0900 and 1300 hours UTC.

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

Category: GB2RS Propagation News

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