Propagation News – 28 January 2024
We dodged a bullet last week when a coronal mass ejection, or CME, was predicted to be heading our way. In the end, it came to nothing.
The CME observed on the 20 January was expected to pass Earth and deliver possible G2 storm conditions. But a solar wind enhancement, possibly associated with the plasma cloud passing near Earth, saw the Kp index rise to only 3.67 on Wednesday 24 January.
The many solar flares, and associated coronal mass ejections, over the past few days makes it difficult to give a reliable geomagnetic forecast. Over the past seven days, there have been more than 60 C-class and 18 M-class flares, which is typical for this point in the solar cycle. Sunspot-wise, the solar flux index has remained high, being more than 170 all week.
Critical frequencies have often been exceeding 11MHz during daylight hours, which means the 30m band, as well as the 40m band, should be open around the UK. However, night-time critical frequencies have fallen below 4MHz, meaning that even the 80m band struggles at times.
We mentioned last week that the NCDXF beacon VK6RBP in Australia had been heard on 28.200MHz. If you’ve copied VK6RBP you might be interested in trying for some other lower-power Australian beacons on the 10m band. Try listening for the 8W VK4LA/B on 28.206MHz in Brisbane, or perhaps the 10W VK4RST, which is 550km north-west of Brisbane, on 28.266MHz.
Next week, NOAA predicts the solar flux index will be in the range of 155 to 175. Geomagnetic conditions are forecast to be quiet, other than on the 29 January when the Kp index is predicted to rise to three. But, as always, keep an eye on solarham.net for a near real-time report.
VHF and up
Today, the 28 January, sees the UK recovering from the two named storms and just getting settled into moving high pressure across northern France, with a second centre crossing central Britain early next week. This offers a chance of Tropo, especially in the south, while fronts continue to affect Scotland.
After the middle of the coming week, a more unsettled pattern returns with fronts crossing the country, which might bring some rain scatter for the GHz bands. But, in general, the picture remains unsettled into the end of the week and doesn’t look too exciting for the 432MHz Affiliated Societies Contest on Sunday 4 February.
Other propagation modes that are worth considering are all relatively low-key in the transition into February. This means that meteor scatter is best looked for in the early pre-dawn period when random meteor activity peaks.
The other chance might be aurora, and this is simply about checking the behaviour of the Kp index, which measures the disturbance of the earth’s magnetic field by solar activity. Kp indices higher than six are a good sign for aurora.
It continues to look like we are in a quiet period for Sporadic-E propagation.
For EME operators, Moon declination is positive and falling, going negative again on the 30 January. Path losses reach their maximum at apogee on Monday 29 January, then start to fall again. 144MHz sky noise is low all week.
Category: GB2RS Propagation News
