Propagation News – 27 April 2014

Several large and magnetically complex sunspot regions were visible during the period but only one M class solar flare took place and that was a M7 on the 18th, however, numerous C class solar flares took place every day. Only one new sunspot region appeared during the week. Solar flux levels declined from 172 units on the 18th to 130 by the 24th. The average was 153 units. The 90 day solar flux average on the 24th was 156, that’s one unit up on last week. X-ray flux levels varied little day to day and averaged B7.6 units. Geomagnetic activity started at quiet levels but during the 19th a coronal mass ejection arrived that departed the Sun several days earlier. The Ap index for the 20th and the 21st was 21 and 22 units respectively. Quiet conditions returned from the 22nd. The average was 12 units. Solar wind data from the ACE spacecraft saw solar wind speeds increase from 360 kilometres per second on the 18th to 760 by the 20th. Speeds then gradually declined to 380 kilometres per second by the 24th. Particle densities were moderate at around 18 particles per cubic centimetre for the first four days but then declined to below 10 particles per cubic centimetre for the rest of the period. Bz varied between minus 8 and plus 21 nanoTeslas on the most disturbed day and between minus 2 and plus 5 nanoTeslas on the quietest day.

Finally, the solar forecast for the coming week. This week the quiet side of the Sun is expected to be looking our way. Solar flux levels are expected to decline to around the 110 mark but towards next weekend levels should start to increase. Geomagnetic activity is expected to be mostly quiet with no coronal hole disturbances and coronal mass ejections expected. MUFs during daylight hours at equal latitudes should be around 26MHz. Darkness hour lows are expected to be about 14MHz. Paths this week to the Middle East should have a maximum usable frequency with a 50 percent success rate of around 24MHz. The optimum working frequency with a 90 percent success rate will be about 18MHz. The best time to try this path will be between 1000 and 1500 hours. Anytime now the start of the summer sporadic E season is expected to commence.

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

Category: GB2RS Propagation News