GB2RS Propagation News
Propagation News – 18 May 2025
This week, you could be forgiven for thinking that the Solar Cycle 25 maximum is now over. With a reduced solar flux index, and an almost blank Sun, there was little to get excited about. By Thursday 15 May, the SFI was 122 but previously, on the 12 May, it had been down to 116 […]
Propagation News – 11 May 2025
Active region 4079 turned out to be not quite so bad as we had predicted. The sunspot was large, about ten times the width of our Earth, so we expected it to be more active. It was regions 4081 and 4082 that produced most of the flare activity last week. Two filament eruptions also occurred […]
Propagation News – 4 May 2025
After the previous week’s geomagnetic disturbances, as described in last week’s GB2RS, the last seven days have been relatively quiet. The Kp index has mostly been in the ones and twos, however the rise to a Kp value of four on Thursday 1 May could herald a return to unsettled conditions. The solar flux index […]
Propagation News – 27 April 2025
We had yet another week of unsettled geomagnetic conditions. The Kp index peaked at 5.33 on the 21 April as the solar wind speed hit just above 600 kilometres per second, and active geomagnetic conditions were observed. This was caused by a massive coronal hole on the Sun’s surface, which measures nearly 700,000km in length. […]
Propagation News – 20 April 2025
Last week was characterised by increased Kp index numbers and severe geomagnetic storms, peaking at G4. These drove down maximum usable frequencies and disrupted DX contacts, especially on the higher HF bands. The solar wind speed increased from 380 kilometres per second to around 500 kilometres per second on 15 April and an increase in […]
Propagation News – 13 April 2025
A fast solar wind caused some disruption last week, often sending the Kp index up to five, with many three-hour periods in excess of four. The solar wind speed was in the 600-700 kilometres per second range, which caused a moderate, G2, geomagnetic storm and visible aurora at higher latitudes mid-week. Glancing CMEs that left […]
