HF News
We had another week of mixed geomagnetic conditions. The Kp index rose to a high of five with a visible aurora over the UK at times.
Two large coronal holes are both facing Earth. A solar wind stream flowing from these zones is expected to flow past Earth, possibly on Friday the 28th or March 1st. Active geomagnetic conditions (Kp4) are currently forecast for this weekend.
There has also been more solar flare activity over the past seven days with an X2-class flare on the 23rd and 10 M-class flares. The X-class flare occurred at 19:27hrs UTC so had little effect in Europe as the Sun had set. An associated coronal mass ejection was not Earth-directed luckily.
Another fast-moving CME on the 24th was also not Earth-directed.
As we enter March it still looks as though the Sun is still very active. The solar flux index stood at 180 on Thursday the 27th, after hitting 210 on the 23rd. Maximum usable frequencies over 3,000km are still reaching 34-35MHz around midday, while night-time MUFs are generally around 10-11MHz, with occasional openings on 20 metres.
This week Raisa (R1BIG) was operating as 3F3RRC in Panama on the RRC Central American Tour 2025 and was worked on 14.180MHz SSB. The team is active until March 3. Bob VP8LP on the Falkland Islands has also been active on 10 metres SSB and has been worked from the UK.
As we enter March this is a good time for North-South paths on HF, such as UK to South Africa and UK to South America. The spring equinox is also a good time for auroral conditions.
Next week. NOAA predicts the Sun will start the week with an SFI of 190, perhaps falling to 170-180 as the week progresses. We hesitate to say this, but geomagnetic conditions are predicted to be good once we get past the disturbances on the 28th/1st – only time will tell!
VHF and up
There is likely to be a welcome return of high pressure for much of the period from this weekend until near the end of the coming week on the 5th.
Models are trying to bring a return of unsettled Atlantic weather, meaning lows, fronts, showers and rain scatter for the Ghz bands. Until then, it will be typical high-pressure Tropo conditions with an extensive temperature inversion aloft caused by the descending warming air in the high-pressure region.
This should provide ducting conditions over a large part of the country. As often, the far north of the UK will probably just miss out and retain too much breeze for the inversion to be effective.
The lull in meteor shower activity continues, so once again your best chances will be in the morning hours around, or just before, dawn.
The Sun has kept aurora seekers busy and shows how frequently it can just tip into the right disturbed conditions at this stage of the solar cycle. As we said earlier, there have been reports of visible aurora in the past week.
The signs for this are the Kp index rising to five or greater and a flutter on LF band signals or trans-polar paths on the HF bands to the recent Pacific DX activity.
The new Sporadic-E season is almost upon us, but we are not there yet. Check the graphs on Propquest for signs of enhanced foEs values and check the HF bands first, 10m is particularly good for strong European Es signals.
EME conditions will be predictable as usual, with Moon declination rising all week and path losses at their minimum at perigee late on Saturday the 1st of March. 144MHz sky noise is low from this coming weekend, rising to moderate by Friday the fifth.
And that’s all from the propagation team this week.