Propagation News – 14 August 2022
The geomagnetic disturbance we predicted last week, due to an Earth-facing coronal hole and its associated high-speed solar wind, occurred in the early hours of Monday the 8th. This pushed the Kp index to six and sparked a visible aurora that was visible from parts of the UK. It also impacted the Maximum Useable Frequency on Monday, according to the Fairford ionosonde, with it struggling to get much above 18MHz over a 3,000km path until the early evening. The Kp index remained mainly at four on Tuesday before tailing off gradually to reach two on Thursday.
Meanwhile, the solar flux index has been slowly declining, from 116 on Sunday to 108 on Thursday.
Sporadic-E has been bringing short skip to 14MHz, with paths such as the UK to Ireland and Scotland being workable at times.
The best DX has probably been on 21MHz where the Far East has been putting in an appearance, mainly on FT8. 28MHz Sporadic-E has been just that, sporadic, with some days providing great short skip to parts of Europe and others just the sound of noise on 10 metres.
Next week NOAA predicts similar conditions with the SFI in the range 104-108. Unsettled geomagnetic conditions are forecast for the 17th, 18th and 19th when the Kp index could rise to five.
VHF and up
The weather will show a more unsettled side from this weekend. The exceptionally widespread Tropo conditions of last week are likely to decay as pressure falls and by the start of the coming week, it’s a slack region of low pressure over us.
This will introduce some mainly showery outbreaks of rain, but in true summer style, they could be heavy and perhaps thundery in places. This raises the prospects for rain scatter on the GHz bands and, as usual, you will need to access one of the many online radar displays to track their movement.
Recent solar conditions have varied, but some occasional aurora alerts have maintained an interest for auroral propagation. Keep a check on the Kp index to see if it goes above five or six and then look at the clusters and chatrooms for activity pointers.
Sporadic-E is still about on some days and well worth your attention for tracking down those missing grid squares. Although we are nearer the end than the start of the Es season, it can occur until about the end of the first week in September, so plenty of time left.
In the coming week, the location of the jet stream activity (often a good guide) suggests that paths may move away from Scandinavia and eastern Europe and favour Spain and the central Mediterranean.
As we slide gently away from the broad peak of the Perseid meteor shower, it’s still worth checking meteor scatter propagation during the coming week.
Moon declination goes positive again on Monday, producing lengthening Moon windows. EME is for early birds this week with Moon zenith in the early hours. Path losses will fall all week, and 144 MHz sky noise is low, not reaching 500 Kelvin until next Sunday.
Category: GB2RS Propagation News
