Propagation News

| January 20, 2013

And now the solar factual data for the period from Friday the 11th to Thursday the 17th of January, compiled by Neil Clarke, G0CAS on Friday the 20th of January. 

Sunspot groups gradually disappeared from ten groups at the start of the period to only five by the end. Two large and magnetically complex groups remained visible every day but failed to produce any sizeable flares. They did though produce two small M class solar flares on the 11th and again on the 13th. Numerous C class solar flares took place every day except for the 17th when solar activity was very low. Solar flux levels declined from 172 units on the 11th to 123 by the 17th. The average was 150 units. The 90 day solar flux average on the 17th was 123, that’s two units up on last week. X-ray flux levels declined from B9 units on the 11th to B2.9 by the 17th. The average was B5.9 units. Geomagnetic activity was quiet every day till the 17th when a coronal mass ejection arrived that departed the Sun on the 13th and the Ap index was 15 units. The average was Ap 7 units. Solar wind data from the ACE spacecraft saw solar wind speeds increased from 280 kilometres per second on the 11th to 550 by the 15th. Particle densities were around or slightly above 10 particles per cubic centimetre every day but on the 17th increased to 45 particles per cubic centimetre. Bz showed little variation except for the 17th which varied between minus 14 and plus 11 nanoTeslas.

And finally the solar forecast for the coming week. This week the quiet side of the Sun is expected to be looking our way. Solar activity should be at low levels with only occasional C class solar flares taking place most days. There is only a small chance of any large solar flares occurring. Solar flux levels should decline and be in the 110’s for most of the week. Geomagnetic activity could be unsettled today due to a coronal mass ejection that departed the Sun on the 16th, otherwise, conditions are expected to be at quiet levels. MUFs during daylight hours at equal latitudes should be around 25MHz for the south and 22MHz for the north. Darkness hour lows should be about 8MHz. Paths this week to South Africa should have a maximum usable frequency with a 50 per cent success rate of around 32MHz. The optimum working frequency with a 90 per cent success rate of about 24MHz. The best time to try this path will be between 110 and 1600 hours.

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

Category: GB2RS Propagation News