Propagation News

| December 9, 2012

And now the solar factual data for the period from Friday the 30th of November to the 6th of December compiled by Neil Clarke, G0CAS on Friday the 7th of December.

Three small new sunspot groups appeared during the period. Solar activity was low and only small occasional C class solar flares took place. These had very little effect on propagation. In total only 9 C class solar flares took place during the period. Solar flux levels declined from 111 units on the 30th to 96 by the 4th and the 5th. The average was 100 units. The 90 day solar flux average on the 6th was 120 units, that’s three units down on last week. X-ray flux levels also declined, from B3.4 units on the 30th to B1.2 by the 6th. The average was B1.8 units. Geomagnetic activity was quiet every day, the Ap index on the 5th and the 6th was only one unit. The most disturbed day was the 2nd with an Ap index of 7 units. The average was Ap 3 units. Solar wind data from the ACE spacecraft saw solar wind speeds vary between 290 and 460 kilometres per second. Particle densities were at elevated levels during most days with 23 particles per cubic centimetre on the 30th, 40 on the 2nd and 22 on the 4th. Only the 5th and the 6th were levels below 10 particles per cubic centimetre. As expected with a quiet geomagnetic field, Bz showed only modest fluctuations throughout the period.

And finally the solar forecast for the coming week. This week the active side of the Sun is expected to be rotating into view. Solar activity is expected to be low, with only C class solar flares taking place. There are no indications that activity would increase any higher than moderate levels on the occasional day. Solar flux levels should increase and be in the 120’s for most of the week. Geomagnetic activity should be quiet today but then a small recurring coronal hole is expected for the next couple of days. However, the disturbance is expected to be very weak. Activity should then decline to quiet levels for the remainder of the week. MUFs during daylight hours at equal latitudes should be around 25MHz for the south and 22MHz for the north. Darkness hour lows should be around 8MHz. Paths this week to South America should have a maximum usable frequency with a 50 per cent success rate of around 30MHz. The optimum working frequency with a 90 per cent success rate will be about 24MHz. The best time to try this path will be between 1100 and 1600 hours.

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

Category: GB2RS Propagation News

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