Propagation News 11 May 2014

Every day a new sunspot region appeared, some small, some much larger and complex. Solar activity was low until a M1 class solar flare took on the 6th and the 7th, which increased activity to moderate. Meanwhile, at the opposite side of the Sun a large sunspot region was rotating into view and on the 8th activity increased to high when a M5 class flare took place. Solar flux levels increased from 132 units on the 4th to 148 by the 8th. The average was 139 units. The 90 day solar flux average on the 8th was 150, that’s four units down on last week. X-ray flux levels increased from B5.4 units on the 2nd to B8.3 by the 7th. The average was B6.9 units. Geomagnetic activity started at quiet levels but on the 4th activity increased to unsettled levels with an Ap index of 16 units. This was probably due to a weak coronal mass ejection that departed the Sun several days earlier. Activity then declined to quiet levels until the 8th when activity increased again with an Ap index of 20 units. The average was Ap 9 units. Solar wind data from the ACE spacecraft saw solar wind speeds vary between 300 and 400 kilometres per second. Particle densities were low on the 2nd but then increased to peak at 60 particles per cubic by the 5th. Bz varied between minus and plus 4 nanoTeslas on the quietest day and between minus 12 and plus 8 nanoTeslas on the 8th.
Finally, the solar forecast for the coming week. This week Solar activity is expected to be low to moderate, with several sunspot groups capable of producing M class solar flares: the question is, though, will they? Solar flux levels should increase and be around the 150s for most of the week. Geomagnetic activity should be at ‘active’ levels for the next few days due to a coronal hole. Activity should then decline to quiet levels but the chance of a coronal mass ejection heading our way is possible all week. MUFs during daylight hours at equal latitudes should be around 25MHz. Darkness hour lows are expected to be about 13MHz. These figures could be slightly lower if any geomagnetic activity continues for a number of days. Paths this week to South America should have a maximum usable frequency with a 50 per cent success rate of around 28MHz. The optimum working frequency with a 90 per cent success rate will be about 21MHz. Sporadic E should take place on a number of days this week with openings on 70MHz possible.
And that’s all for this week from the propagation team.

Category: GB2RS Propagation News