Propagation News – 27 July 2014

| July 25, 2014

The Sun had another quiet week, with solar activity very low. Spots were few and there were six successive days when no solar flares were reported until a, small C-class occurred on the 24th. After last week’s precipitate drop, the solar flux was more stable. It began the week at 89 units and ended at 104, averaging 93. The 90-day average was 129 units on the 24th—a drop of 4 points. The X-ray flux was down from an average of B6.0 to B1.7.

The one bright spot was that geomagnetic activity again remained low, with the Ap index in single figures every day, averaging only 4 units. Apart from the occasional spike, particle densities were consistently low. Solar wind speeds were below average, ranging between 270 and 355km/sec. Bz showed little daily variation, mostly ranging between plus and minus 5 nanoTeslas. There were occasional sporadic-e opening, sometimes reaching 70MHz, and, more frequently, 50MHz.

Now the forecast. In the course of the coming week the more active face of the Sun should be beginning to turn towards us, bringing the return of areas that produced considerable activity during the last rotation. The solar flux should see a steady increase, possibly into the 130s. It seems likely that the flare count will increase, with solar activity at times up to moderate level. Geomagnetic activity will mostly remain low. Daytime MUFs at equal latitudes are expected to be in the vicinity of 24MHz, while darkness lows will be about 14MHz. Paths to Japan this week should have a Maximum Usable Frequency, with a 50 percent chance of success, of 20MHz. The Optimum Working Frequency with a 90 percent prospect of a contact, will be about 14MHz. The path should be best between 0600 and 1200UTC.

There remains a fair possibility of sporadic-e on 28MHx and the lower VHF bands.

Category: GB2RS Propagation News