RSGB
RadCom Assistant Editor | March 20, 2026
Last weekend’s Commonwealth Contest got off to a bad start, thanks to a Kp index of 6 that really affected the ionosphere.
As a result, HF conditions were not good with the maximum usable frequency over a 3,000km path below 21MHz until 1700UTC. Luckily, things improved a little on Sunday but overall scores were down compared with previous events.
The Kp index increase was due to a coronal hole stream which reached 600 to 700km/second and a Bz that pointed south. The equinox period hasn’t helped due to the Russell-McPherron effect, a phenomenon that occurs when the Earth’s magnetic field aligns with the Sun’s magnetic field during equinoxes, creating ‘cracks’ in the magnetosphere.
Otherwise, the week has been unremarkable. The solar flux index has remained firmly in the 110s and there have been no X-class solar flares, only a few M and lesser C-class events.
Next week, HF propagation may be dominated again by the solar wind. Coronal hole number 33 will begin to face Earth and a high-speed stream was predicted to reach us this weekend, ending today, 22 March. A coronal mass ejection was also predicted to arrive around Thursday, 19 March.
NOAA predicts the Kp index will rise to 5 this weekend and not decline to 3 until 26 March. Meanwhile, the solar flux is predicted to remain in the 105 to 120 range until 27 March. It may then increase slightly to be in the 120s until the end of the month.
As a result, expect lower maximum usable frequencies and poorer HF conditions until around next Thursday and Friday, 26-27 March.
VHF and up propagation news from G3YLA and G4BAO:
The high pressure that developed during the second half of last week formed on the warmer side of the front and as a result produced slightly better tropo conditions than looked possible the previous week.
The weather is probably going to try to change to a colder air high in the coming week, so expect conditions to decline. However, that’s not the only reason for a decline.
As the main high centre displaces west of Britain, we will find a colder and unsettled west or northwesterly pattern affecting the UK next week. So less tropo, but more chance of some rain scatter for the upper GHz bands.
Meteor scatter remains in the random activity domain, although we are edging closer to the next major shower of the late April Lyrids.
It’s not to say that exciting things can’t happen, however. Just after a HamSCI workshop on the subject of meteor scatter last weekend, a multi-ton meteoroid was reported from Cleveland, Ohio, on the HamSCI Google groups at around 1300UTC on 17 March.
This produced a sonic boom and was visible in broad daylight.
All is quiet on the Sporadic-E front, although we are slowly moving towards a period when the first glimmers of activity show themselves, particularly on digital modes.
Lastly, a comment on the chances of aurora. These are usually enhanced due to solar-terrestrial alignment around the equinoxes and with two coronal mass ejections predicted to arrive at the tail end of last week, ending today, 22 March. As usual, check for an increasing Kp index above 5.
For EME, yesterday saw the 5.7GHz section of the Dubus CW and SSB EME contest and associated all-mode activity weekend.
With Moon declination positive and rising, and path losses still low, it hopefully produced some nice contacts.
On VHF, 144MHz sky noise is low in the coming week.
https://rsgb.org/main/blog/news/gb2rs/propagation-news/2026/03/20/propagation-news-15-march-2026-2/
(Mike Terry, UK/BDXC)
