Propagation News – 29 June 2014

| June 27, 2014

By the 24th only three sunspot regions were visible and these were only producing the occasional C-class solar flares most day. In fact, on the 22nd and the 25th solar activity declined to very low levels when no C class solar flares took place. In total 10 C class solar flares took place during the period. Solar flux declined from 102 units on the 20th to 94 by the 24th. The average was 97 units. The 90 day solar flux average on the 26th was 133 units, that’s four units down on last week. X-ray flux levels declined slightly to B1.6 units and the average was B2 units. Geomagnetic activity quiet everyday, the most disturbed day was the 20th with an Ap index of 9 units. The average was Ap 6 units. Solar wind data from the ACE spacecraft saw solar wind speeds increase from 400 kilometres per second on the 20th to 500 by the next day, speeds then declined to 300 kilometres by the 25th. Particle densities were moderate to high most days with a peak of 50 particles per cubic centimetre on the 25th. Bz showed only modest fluctuations throughout the period with minus 7 and plus 8 nanoTeslas recorded on the 20th.

Finally, the solar forecast for the coming week. This week should see the more active side of the Sun coming into view. Several active sunspot groups are expected to rotate into view. Solar activity is expected to be mostly low but could increase to moderate on the occasional days. Solar flux levels should increase and be in 130s later in the week. Geomagnetic activity is expected to be mostly quiet with the Ap index in single figures every day. MUFs during daylight hours at equal latitudes should be around 21MHz. Darkness hour lows should be about 13MHz. Paths this week to South America should have a maximum usable frequency with a 50 percent success rate of around 27MHz. The optimum working frequency with a 90 percent success rate will be about 21MHz. The best time to try this path will be between 1400 and 2200 hours. Sporadic-E should take place on most days.

Category: GB2RS Propagation News

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