Propagation News – 22 June 2014

| June 20, 2014

Solar activity started at moderate levels when a single M class solar flare took place on the first four days of the period, however, from then the active sunspot regions rotated out of view. From the 17th, solar activity was low. In total 52 C class solar flares took place. Solar flux levels declined from 153 units on the 13th to 111 by the 18th and the 19th, the average was 126 units. The 90 day solar flux average on the 19th was 137, that’s two units down on last week. X-ray flux levels declined from C1.2 units on the 14th to B2.5 by the 19th. The average was B7.2 units. Geomagnetic activity was quiet at first with the Ap index in single figures but on the 18th a coronal hole disturbance occurred. The Ap index was 15 units on that day. The average was Ap 9 units. Solar wind data from the ACE spacecraft saw solar wind speeds increase from 340 kilometres per second to 500 by the 17th. Particle densities were moderate most days and varied between 10 and 28 particles per cubic centimetre. Bz varied between minus 4 and plus 5 nanoTeslas on the quietest day and between minus and plus 10 nanoTeslas on the 18th, which was the most disturbed day.

Finally, the solar forecast for the coming week. This week the quiet side of the Sun is expected to rotate into view. Solar activity is expected to be mostly low but on the occasional day increase to moderate levels. Solar flux levels may dip to around 100 units around midweek before increasing next weekend. Geomagnetic activity is expected to be mostly low but during the second half of the week a small recurring coronal hole disturbance is expected. MUFs during daylight hours at equal latitudes should be about 21MHz. Darkness hour lows should be about 14MHz. Paths this week to Australia should have a maximum usable frequency of around 20MHz. The optimum working frequency with a 90 percent success rate will be about 15MHz. The best time to try this path will 0600 and 1000 hours UTC.

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

Category: GB2RS Propagation News