Propagation News – 7 July 2013

| July 4, 2013

And now the solar factual data for the period from Friday the 28th of June to Thursday the 4th of July compiled by Neil Clarke, G0CAS on Friday the 5th of July.

Midway through the period, the first of a couple of large complex regions rotated into view. As a result solar activity increased to moderate levels when a M1 class solar flare took place on the 3rd. Also, numerous C class solar flares have taken place. Solar flux levels increased from 100 units on the 29th to 138 by the 4th. The average was 113 units. The 90 day solar flux average on the 4th was 122 units, that’s one unit down on last week. X-ray flux levels increased from B1.9 units on the 29th to B7.7 by the 4th, the average was B4.2 units. Geomagnetic activity started at major storm levels with an Ap index of 66 units on the 29th. The activity was due to a coronal mass ejection and the effects from a coronal hole. By the 2nd activity had subsided to quiet levels with an Ap of 4 units on the 2nd and the 3rd. The average was Ap 18 units. Solar wind data from the ACE spacecraft saw solar wind speeds increase to 600 kilometres per second by the 30th but then decline to 340 by the 4th. Particle densities were moderate at first with 22 particles per cubic centimetre on the 29th. Bz varied between minus 12 and plus 5 nanoTeslas on the 29th. The reason for such an high Ap on that day was due to the fact that the Bz remained negative from 0600 on the 29th till midday on the 30th.

And finally the solar forecast for the coming week. There is a complex area that contains several sunspot groups, and a couple of which are large and complex. Therefore, this week there is a good chance of solar activity increasing to moderate levels or even increasing to high on the occasional day.  Solar flux levels are expected  increase and be around the 150s. Geomagnetic activity is expected to be mostly quiet, however, if a coronal mass ejection heads our way then activity would increase. MUFs during daylight hours at equal latitudes should be about 23MHz for the south and 20MHz for the north. Darkness hour lows should be around 14MHz. Paths this week to South Africa 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 around 24MHz. The best time to try this path will be between 1000 and 1600 hours UTC. Sporadic-E is expected to take place on most days with still the occasional chance of openings up to 144MHz.

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


Category: GB2RS Propagation News