Propagation News

| October 28, 2012

And now the solar factual data for the period from Friday the 19th to Thursday the 25th of October, compiled by Neil Clarke, G0CAS on Friday the 26th of October

Solar activity was moderate to high with an X1 class solar flare taking place early on the 23rd. This is the first X class solar flare since the 12th of July and is the sixth of the year. In total 3 M class flares and numerous C class solar flares took place. Solar flux levels increased from 141 units on the 19th to 156 by the 22nd, levels then gradually declined to 130 units by the 25th. The average was 143 units. The 90 day solar flux average on the 25th was 122 units, that’s three units up on last week. X-ray flux levels peaked early in the period at B6.1 units on the 20th and then gradually declined to B3.8 by the 25th. The average was B5.4 units. Geomagnetic activity was quiet every day. The quietest day was the 20th with an Ap index only 1 unit. On three days the Ap was 2 units. The most disturbed day was the 23rd with an Ap index of 6 units and the average for the period was 3 units. Solar wind data from the ACE spacecraft saw solar wind speeds decline from 500 kilometres per second at the start of the period to 320 by the end. Particle densities were low every day and the Bz never varied more than minus 4 and plus 5 nanoTeslas. As they approached their autumn peak the HF bands were in good shape throughout, with some excellent openings on 10 metres.

And finally the solar forecast for the coming week. This week the more active side of the Sun is expected to rotate out of view. Solar activity is expected to be predominately at low levels but there are still visible sunspot groups that could increase activity to moderate levels on some days. Solar flux levels should decline most days to around the 100 mark later in the week. Geomagnetic activity on the whole should be quiet, however, if a large solar flare and an associated Earth directed coronal mass ejection takes place then activity would increase. No coronal hole disturbances are expected. MUFs during daylight hours at equal latitudes should be around 30MHz, or slightly higher on some days. Darkness hour lows should be about 8MHz. Paths this week to India should have a maximum usable frequency with a 50 per cent success rate will be around 29MHz. The optimum working frequency with a 90 per cent success rate will be about 13MHz. The best time to try this path will be between 1000 and 1300 hours UTC.

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

Category: GB2RS Propagation News

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