Propagation News

| October 21, 2012

And now the solar factual data for the period from Friday the 12th to Thursday the 18th of October, compiled by Neil Clarke G0CAS on Friday the 19th of October

Seven new sunspot groups appeared during the period, however, solar activity was low on most days with a number of C class solar flares taking place, except for the 13th when none took place and, as a result, solar activity was very low. Solar flux levels increased from 122 units on the 12th to 138 by the 18th. The average was 132 units. The 90 day solar flux average on the 18th was 119, that’s one unit up on last week. X-ray flux levels showed little variation day to day and averaged B4.7 units. Geomagnetic activity increased to ‘minor storm’ levels at mid latitudes and ‘severe storm’ levels at high latitudes on the 13th with an Ap index of 52 units. Activity gradually declined and was at quiet levels from the 15th. The average was Ap 15 units. The solar wind data from the ACE spacecraft saw wind solar wind speeds increase from 400 kilometres per second on the 12th to 600 during the evening of the 13th. Particle densities were low every day. Bz, which is the magnetic component of the solar wind, was minus 5 and plus 3 nanoTeslas on the quietest day and between minus 12 and plus 9 nanoTeslas during the disturbance. Except for the 13th, MUFs reached predicted values and some trans-Atlantic working was reported at 28MHz. VHF aurora was reported, particularly on the morning of the 13th but, since this was only a mild disturbance, few contacts – if any – were reported from the UK.

And finally the solar forecast for the coming week. The active side of the Sun is still expected to be looking our way. Saying that, solar activity is expected to be at low to moderate levels, with occasional M class solar flares taking place on the odd day. Solar flux levels should increase and be around the 150’s later in the week. Geomagnetic activity is expected to be mostly quiet, however, if a coronal mass ejection heads our way then activity would increase. MUFs during daylight hours at equal latitudes should be around 30MHz or even slightly higher. Just a reminder that daytime highs normally take place around local noon during the winter months. Darkness hour lows should be about 8MHz. Paths this week to South America should have a maximum usable frequency with a 50 per cent success rate of around 35MHz. The optimum working frequency with a 90 per cent success rate will be about 27MHz. The best time to try this path will be between 1100 to 1600 hours UTC.

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

Category: GB2RS Propagation News

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