Propagation News

| December 6, 2013

The largest sunspot group visible during the period remained very quiet and produced no significant solar flare activity. However, some smaller groups produced a couple of C class solar flares every day when solar activity was at low levels. Solar flux levels increased from 129 units on the 29th to 150 by the 5th. The average was 136 units. The 90 day solar flux average on the 5th was 130 units, that’s two unit up on last week. X-ray flux levels increased from B3.5 units on the 29th to C1 units by the 5th, the average was B5.3 units. The geomagnetic field was quiet every day, the most disturbed day was the 1st with an Ap index of 8 units. The average was Ap 5 units. Solar wind data from the ACE spacecraft saw solar wind speeds increase from 260 kilometres per second on the 29th to 460 by the 2nd. Particle densities decreased from 34 particles per cubic centimetre on the 29th to below 10 particles per cubic centimetre for the remainder of the period. Bz varied between minus and plus 9 nanoTeslas on the 1st which was the most disturbed day to between minus and plus 5 nanoTeslas on the quietest day. For most of the period a high pressure system brought extended tropo conditions at VHF and UHF, with a particular focus on Germany.

Finally, the solar forecast for the coming week. This week the active side of the Sun is expected to be looking our way. Solar activity is expected to be moderate on some days. Solar flux levels should be around the 150′s for most of the week. Geomagnetic activity could be unsettled today and tomorrow due a small recurring coronal hole, also, activity would increase if a coronal mass ejection heads our way. MUFs during daylight hours at equal latitudes should be around or slightly higher than 30MHz. 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 36MHz. The optimum working frequency with a 90 per cent success rate will be about 29MHz. The best time to try this path will be between 1100 and 1600 hours UTC.

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

Category: GB2RS Propagation News