Propagation News

| September 30, 2012

And now the solar factual data for the period from Friday the 21st to Thursday the 27th of September, compiled by Neil Clarke on Friday the 28th of September.

This week solar activity started at very low levels on the 21st and the 24th. However, on the 23rd as sunspot groups rotated into view solar activity increased to low with occasional small C class solar flares taking place everyday. Solar flux levels increased from 117 units on the 21st to 140 by the 25th. The average was 132 units. The 90 day solar flux average on the 27th was 124 units, that’s two units up on last week. X-ray flux levels increased from B2.5 units on the 21st to B4.6 by the 25th. The average was B3.7 units. Geomagnetic activity was quiet everyday and the average was Ap 5 units. Solar wind data from the ACE spacecraft saw solar wind speeds decrease from 560 kilometres per second to 300 by the morning of the 26th. Speeds then increased to peak at 480 kilometres per second later the same day. Particle densities were low everyday. Bz varied between minus 8 and plus 9 nanoTeslas on the 26th. Fluctuations were less than this on the quieter days as expected.

And finally the solar forecast from Sunday the 30th of September. This week the active side of the Sun is expected to be looking our way. In recent days large sunspot groups have rotated into view. Solar activity should be low but could increase to moderate levels on the occasional day. Solar flux levels are expected to be at their highest for this solar rotation and be in the 130’s at first but may decline as the week goes on. Geomagnetic activity is expected to be quiet but a recurring coronal hole is expected later in the week, however, the disturbance is expected to be small. MUFs during daylight hours at equal latitudes should be around 28MHz for the south and 25MHz for the north. Darkness hour lows should be about 10MHz. 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 26MHz. The optimum working frequency with a 90 per cent success rate will be about 21MHz. The best time to try this path will be between 1500 and 1900 hours UTC.

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

Category: GB2RS Propagation News

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