Propagation News – 3 August 2014

As predicted, two large sunspot regions rotated into view, one on the 27th and the other on the 30th. Solar activity started at low levels with a small number of C class solar flares taking place each day. However, on the 31st, activity increased to moderate levels when a M2 class solar flare took place just before midday. Solar flux levels increased from 107 units on the 25th to 156 by the 31st. The average was 132 units. The 90 day solar flux average on the 31st was 130, that’s one unit up on last week. X-ray flux levels increased from B2.8 units on the 25th to B7.1 by the 30th, the average was B5 units. Geomagnetic activity was quiet every day, though, on the 28th activity increased slightly with an Ap index of 10 units. The average was Ap 6 units. Solar wind data from the ACE spacecraft saw solar wind speeds vary between 310 and 470 kilometres per second. Particle densities were low except for a brief increase to 60 particles per cubic centimetre on the 28th. Bz varied between minus 8 and plus 12 nanoTeslas on the 28th which was the most disturbed day and between minus 5 and plus 3 nanoTeslas on the quietest day.

Now the solar forecast for the coming week. This week solar activity is expected to be at moderate levels on some days. This is due to the two old returning sunspot groups that produced M class solar flares on their last rotation. Solar flux levels should be around the 160’s at first but could start to decline after midweek. Geomagnetic activity should start at quiet levels but by midweek increase slightly due to a recurring coronal hole. MUFs during daylight hours at equal latitudes should be around 23MHz. Darkness hour lows should be about 12MHz. Paths this week to the Middle East should have a maximum usable frequency with a 50 percent success rate of around 22MHz. The optimum working frequency with a 90 percent success rate will be about 17MHz. The best time to try this path will be between 100 and 1600 hours.

Category: GB2RS Propagation News