Propagation News – 8 October 2023
Last week progressed quite well from a solar point of view, at least until the morning of Thursday 5 October when the Kp index rose to five.
But the Kp high was short-lived and only lasted for one three-hour reporting period.
Until this point, it had been around one to three all week, which meant the ionosphere had a chance to settle and build. As a result, we saw daytime MUFs over a 3,000km path rise well above 28MHz. This was partly due to the seasonal change, which sees daytime MUFs generally rise as we head towards autumn.
Similarly, we are seeing night-time MUFs declining as we progress through October. The times of seeing the 17 and 20m bands open all night are probably behind us now and they won’t be back until next summer!
The Solar Flux Index held up quite well last week, peaking at 161 on the 1 October, before declining slightly to 155 by Thursday 5 October.
Propagation-wise, we are really starting to benefit from the autumnal changes. Stations worked from the UK recently include the 5W0LM DXpedition to Samoa on 20m CW. The team expects to be on air until the 14 October.
The big one this autumn is the W8S DXpedition to Swains Island, a remote coral atoll in the Tokelau Islands in the South Pacific Ocean. We will look at the propagation prospects for working W8S in the GB2RS News next week.
Next week, NOAA predicts that the Solar Flux Index will remain in the 160s. It also predicts a Kp index of two all week. But, with eight active regions on the Sun at present, the risk of a solar flare and/or Coronal Mass Ejection remains high. So, don’t be surprised if we see the Kp index head skywards again, at times, with a reduction in the maximum useable frequency.
And finally, the good news is that the Chilton Digisonde is now back in action. You can select it, as well as Dourbes, via the website
VHF and up
This first weekend of October could be good for meteor scatter with the peak of the October Draconids tonight, the 8 into the 9 October.
It should also be quite a good period for Tropo as high pressure over the south provides enhanced paths across the continent to France and Germany. There may also be a path across Biscay to Spain or the Canaries and Azores.
Along with fine and unusually warm weather, it should fit in well with the October 432MHz to 245GHz Contest which ends at 1400UTC today, the 8 October. Hopefully there will still be something left for the 432MHz FM Activity Contest and UK Activity Contest on Tuesday the 10 October.
On the evening of Wednesday 5 October, an aurora alert arrived, so clearly that’s another mode to keep in mind. From around the 11 October, we will find a trend towards more unsettled conditions with rain and showers and rather windy weather as low pressure takes charge. This will remove Tropo from the operating schedule but may give some rain scatter opportunities.
For EME operators, Moon declination is just past maximum this coming weekend so, as the following week progresses, Moon elevation will fall from its high and Moon windows will shorten. With apogee on Tuesday 10 October, path losses are at, or around, their maximum. 144MHz sky noise is falling, reaching a minimum next Tuesday. The Sun and Moon are close in the sky on Saturday 14 October meaning high noise all weekend.
Category: GB2RS Propagation News
