Propagation News – 03 April 2022
Last week we said there was a sense of excitement as it looked like the solar flux index would increase. But even NOAA didn’t predict that it would rise to 156, which it hit on Monday the 28th. Unfortunately, along with high sunspot numbers, we have had unsettled geomagnetic conditions. On Sunday and Monday last week, the Kp index hit four, due to the predicted coronal hole issues. By Thursday the 31st, the effects of an M4/M1 coronal mass ejection event from the 28th of March were being felt. This CME resulted from a pair of sunspots, which combined into one larger shock front.
The solar wind speed was above 500km/s and the Bz component of the interplanetary magnetic field shifted south meaning it coupled more easily with the Earth’s magnetic field, pushing the Kp index to five with warnings for middle to high latitude aurora happening.
If this wasn’t enough, we have had a number of solar flares to contend with, including an X1.3 event from active region AR 2975 peaking at 1737UTC on Wednesday the 30th of March. This will likely result in a CME coming our way.
All this has had numerous effects on HF, from fadeouts from the flares, to pre-auroral enhancements from the CMEs and good conditions on 10 metres thanks to the high SFI.
A high f0F2 critical frequency has also meant that 40 metres has been open to inter-G signals at times.
We are now well and truly in a period where it is getting difficult to predict what will happen next. NOAA predicts that the SFI will remain above 120 for the next few days and then decline into the teens. We think the best advice is to keep an eye on solarham.net and watch out for news of CMEs leaving the Sun. Expect unsettled conditions around 48 hours after news of any CME.
But the best advice overall, is just get on the bands and work DX whenever you can! We can often expect MUFs to exceed 28MHz at times so make the most of 10 metres when you can, for example, John, G4BAO reports 10m was wide open to Asia on Thursday morning.
VHF and up
Next week offers a change of wind direction from northerly to westerly with the glimmer of hope for high pressure after the weekend, but it’s only a partial nod towards tropo with just a weak, temporary ridge extending across southern UK from the Azores high.
The next items worth mentioning are as in last week’s bulletin; keep your ears and eyes open for aurora, after a promising end to the last week as we write this with fluttery signals on 80m, you should have sorted out some favourite beacons to listen out for. Also the early mornings can be good for random meteor scatter activity.
As we roll-over into April we are getting a bit closer to the 2022 Sporadic-E season. There have been some isolated examples on 10m CW/SSB and 6m on data modes, so it’s time to start checking the position of jet streams and EPI on the Propquest.co.uk website.
The end of last week favoured paths to the south into Spain across a north westerly jet stream over the Pyrenees and Cantabrian mountains, whereas next week it looks like paths to Scandinavia might be worth a look, although probably a lower probability for these more northern latitudes.
Moon declination is positive all week reaching maximum on Friday, so Moon windows and peak Moon elevation will be high. We are past perigee so path losses will increase throughout the week. 144MHz Sky noise is low all week, briefly hitting 500K on Thursday.
Category: GB2RS Propagation News
