RSGB
GB2RS News Team
July 8, 2022
It was a mixed bag of HF propagation last week. The solar flux index was adequate rather than outstanding and a large elongated coronal hole contributed to the Kp index hitting five on the 4 July. However, things became more settled geomagnetically later in the week with the Kp index back down in the ones and twos. The SFI slowly climbed up to 115 by Thursday, thanks to some new spots appearing over the Sun’s limb.
There was some minor solar flare activity, but no coronal mass ejections were logged. The net result was quite good conditions with the MUF over a 3,000km path reaching up to 24MHz at times. This changed on Thursday, however, when the Kp index rose to five due to the incoming enhanced solar wind.
Earlier in the week there were some reports of trans-Atlantic contacts on 10 metres as well as extensive Es openings into Europe. If the Kp index can once again go low it does rather bode well for the IARU worldwide contest this weekend.
Next week, NOAA predicts that the SFI will remain around 115 for a time, but may then drop back to around 108 as the week progresses.
Barring any CMEs, NOAA predicts that the Kp index may remain low, at least until the 15 and 16 July when it could rise to four again. However, a coronal hole on the Sun’s equator will become Earth facing on Saturday, so we might expect the Kp index to climb around Monday. As always, this is hard to be predict.
VHF and up:
The coming week is likely to see high pressure over southern Britain with occasional lows crossing north of Scotland with rain and stronger winds. This raises the prospect of GHz band rain scatter as the fronts move south and break up into showers over northern England and North Wales.
The main feature of the next week is the high pressure and the prospects of fairly widespread Tropo. This could extend south and east into the continent and south across Biscay to Spain and beyond. Contacts with the Canaries or perhaps even farther to Cape Verde for the big stations in the southwest of the UK and southern Ireland are possible.
The high summer Sporadic-E season is in full swing although somewhat reticent compared to other years. The jet stream activity is not as widespread as earlier in the season now that summer conditions with lighter upper winds are becoming established, but there should be a preference for paths to Scandinavia and southeast Europe.
The other remaining modes of aurora and meteor scatter are of course available given the right conditions. The minor Alpha-Capricornids meteor shower should be active but with a low ZHR of around five. Solar output has been affecting the Kp index recently, so check the various space weather websites for details of further events.
The Moon is at minimum declination on Tuesday and perigee on Wednesday so short Moon visibility windows and low path losses are the story for EME this week. 144MHz sky noise is high for most of the week. (rsgb.org)
