Propagation News – 4 September 2022

The radio propagation report was compiled by G0KYA, G3YLA, and G4BAO
on Friday the 2 September 2022.

Many amateurs thought Christmas had arrived early when a solar flux index of 252 was posted on the 28th of August. This would have been representative of a very good solar maximum. Unfortunately, it wasn’t to be as the previous day’s SFI had been 128 and the following day it was 131.

Solarham.com reported that the figure had been ‘contaminated’ by solar flaring just before the measurement was taken and the lack of excellent DX reports on the higher bands seems to support this. Sorry if you got your hopes up, but meanwhile it is back to sunspot normality, at least for a few years yet!

If we exclude the anomaly, the solar flux varied from a low of 113 on the 31st to a high of 131 on the 29th. Region 3089 has probably contributed most to this, but will be rotating out of view this weekend. It does look as though there are some active regions lurking just over the Sun’s eastern limb, which could push the SFI up over the next week.

There were multiple R1/R2 radio blackouts on Monday the 29th due to M-class solar flares. Unfortunately, a large coronal hole on the Sun’s equator will become Earth-facing on Friday, which could result in the Kp index rising as the plasma hits the Earth, perhaps late on Sunday. This could bring a short-lived ionospheric enhancement, followed by a decline in the MUF as any geomagnetic storm progresses.

Next week NOAA predicts that the solar flux index will be in the range 108-124, so expect similar conditions to last. This may be better later in the week once the geomagnetic conditions settle.

As we head into Autumn, we can expect a general improvement in HF conditions and hopefully the return of trans-Atlantic DX on the higher bands.

VHF and up

The weather this week could become very unsettled. Most models agree on the overall trend towards wetter weather, but the details are going to prove difficult except on a day-by-day basis. 

The reason is that the mechanism of change brings a large slow-moving low over the country at the weekend where it remains for much of next week. For many areas, particularly the east, the rain will be in the form of showers, some heavy, thundery and localised rather than widespread. 

For propagation, this means that rain scatter is a good mode to look at for the GHz bands and the various online radars will tell you where the big storms are, and their movement. 

It does suggest that VHF/UHF Tropo will not be a big player, which presents challenges for those on the 144MHz contests this weekend and the UKAC next week. It is possible that we may find a return of high pressure and perhaps some Tropo from the northwest during the following weekend.

The Sporadic-E season has all but faded away, but keep a watch on 50MHz especially as we approach the UK Activity Contest on Thursday evening since Es have been known to crop up in the first week of September. 

Despite there being no big meteor showers in September, random meteor rates are at their maximum, providing relatively good propagation, especially around dawn. That said, the Aurigids shower reached its peak last week, and the Epsilon-Perseids peaks this coming Friday night. This shower has a history of surprising outbursts.

The Moon is at minimum declination today and at perigee on Wednesday, so expect lowest path losses, but short Moon windows. 144 MHz sky noise is high until Tuesday but low after that. 

Category: GB2RS Propagation News