Propagation News 13 October 2013

Midway through the period two sunspot regions rotated into view and increased in size and magnetic complexity. With it solar activity increased. Solar activity was very low on the 5th but then increased to moderate levels by the 9th when the only M class solar flare took place. Solar flux levels increased from 106 units on the 5th to 121 by the 10th. The average was 111 units. The 90 day solar flux average on the 10th was 110 units, that’s the same level as last week. X-ray flux levels increased from B2 units on the 5th to B4.7 by the 10th. The average was B2.8 units. Geomagnetic activity started the period at quiet levels but late on the 8th a coronal mass ejection arrived that departed the Sun on the 6th and lasted till midday of the 10th. The 9th was the most disturbed day with an Ap index of 26 units. The average was Ap 8 units. Solar wind data from the ACE spacecraft saw solar wind speeds increase from 270 kilometres per second to 680 by the 9th. Particle densities were low except an increase 60 particles per cubic centimetre on the 8th. Bz varied between minus 1 and plus 2 nanoTeslas on the quietest day and between minus 15 and plus 23 nanoTeslas at the height of the disturbance.

Finally, the solar forecast for the coming week. Things are looking a bit more active this week. Solar activity is expected to be low most days, however there is a good chance that activity could increase to moderate levels on the some days. Solar flux levels could increase to around 130 units. Geomagnetic activity could be at unsettled levels today and tomorrow due to the after effects from a coronal hole. The remaining days are expected to be quiet providing a coronal mass ejection does not head our way. 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 9MHz. Paths this week to India should have a maximum usable frequency with a 50 per cent success rate of around 30MHz. The optimum working frequency with a 90 per cent success rate will be about 25MHz. 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