Propagation News – 23 June 2013

| June 21, 2013

And now the solar factual data for the period from Friday the 14th to Thursday the 20th of June compiled by Neil Clarke, G0CAS on Friday the 21st of June.

Solar activity was low everyday with only a small number of C class solar flares taking place each day. Up to seven sunspot groups were visible on the 16th. Solar flux levels increased from 109 units on the 14th to 126 by the 20th. The average was 119 units. The 90 day solar flux average on the 20th was 121 units, that’s the same level as last week. X-ray flux levels increased slightly from B3.1 to B4.6 units by the 17th. The average was B4 units. Geomagnetic activity was quiet everyday until the 20th when a coronal hole disturbance arrived when the Ap was 16 units, the average was Ap 6 units. Solar wind data from the ACE spacecraft saw solar wind speeds increase from a slow 260 kilometres per second on the 17th and the 18th to 530 kilometres per second on the 20th. Particle densities were low except for the 20th, which increased to a high 119 particles per cubic centimetre. Bz varied between minus 5 and plus 3 nanoTeslas on the quietest day and between minus 12 and plus 10 nanoTeslas on the 20th.

And finally the solar forecast for the coming week. This week could see the more active side of the Sun looking our way. Solar activity is expected increase to moderate levels on some days. Solar flux levels could be around the 130s at first but may decline as the week progress. Geomagnetic activity is expected to be unsettled for the next couple of days and again next weekend. Both of these disturbances are due to recurring coronal holes. MUFs during daylight hours at equal latitudes should be about 24MHz for the south and 21MHz for the south. Daytime highs are expected to take place during the evening. Darkness hour lows should be around 14MHz. 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 22MHz. The best time to try this path will be between 1500 and 2000 hours UTC. Sporadic-E is expected most days with openings up to 144 possible on the occasional days.

NASA prepares to launch a new solar satellite, which is due for lift off on the 26th, IRIS, the Interface Region Imaging Spectrograph will observe how solar material moves, gathers and heats up as it travels through the Sun’s lower atmosphere. IRIS carries a multi-band ultraviolet imaging spectrograph. It will be in a polar-synchronous orbit which will take it almost over both poles and will cross the equator at the same place at the same time everyday and will allow an almost continuous solar observations to take place during its two year mission.

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

Category: GB2RS Propagation News

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