Propagation – 12 May 2012

| May 10, 2013

And now the solar factual data for the period from Friday the 3rd to Thursday the 9th of May, compiled by Neil Clarke, G0CAS, on Friday the 10th of May.

Numerous sunspot regions were visible every day. A few were large enough to produce solar flares every day. Solar activity increased to high when a M5 class solar flare took place on the 3rd and a M1 class flare on the 5th when activity was at moderate levels. The remaining days activity was at low levels, with C class solar flares taking place. Solar flux levels declined from 148 units on the 3rd to 127 by the 8th. The average was 135 units. The 90 day solar flux average on the 9th was 117 units, that’s two units up on last week. X-ray flux levels declined from B6.5 units on the 3rd to B4.3 by the 8th. The average was B5.6 units. Geomagnetic activity was quiet every day except for the 7th, when activity increased slightly to unsettled levels due to a small coronal hole. The Ap index for the 7th was 12 units. The average was Ap 8 units. Solar wind data from the ACE spacecraft saw solar wind speeds increase from 330 kilometres per second on the 4th to 600 by the morning of the 6th. Speeds then gradually declined to 420 kilometres per second by the end of the period. Particle densities were low except for a brief increase to 45 particles per cubic centimetre on the 6th. Bz varied between minus 7 and plus 11 nanoTeslas on the 6th during the weak disturbance and between minus 4 and plus 1 nanoTeslas on the quietest day.

And finally the solar forecast for the coming week. This week solar activity is expected to be low, however, there is a reasonable chance of activity increasing on the occasional day. Solar flux levels are expected to be around the 120s but could increase towards next weekend. Geomagnetic activity is expected to be quiet every day. However, if a coronal mass ejection heads our way then activity would increase. MUFs during daylight hours at equal latitudes should be around 23MHz for the south and 20MHz for the north. Darkness hour lows should be about 12MHz. Paths this week to India should have a maximum usable frequency with a 50 per cent success rate of around 22MHz. The optimum working frequency with a 90 per cent success rate will be about 17MHz. The best time to try this path will be between 1100 and 1600 hours UTC. Sporadic-E is expected to take place on some days up to 70MHz. In any intense openings propagation is possible on 144MHz.

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

Category: GB2RS Propagation News

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